Mdm 300 i s инструкция

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MDM300 I.S.
Advanced Dew-Point Hygrometer
User’s Manual
- I.
S.
97213 Issue 5
October 2017
Please fill out the form(s) below for each instrument that has been purchased.
Use this information when contacting Michell Instruments for service purposes.
Hygrometer
Code
Serial Number
Invoice Date
Location of Instrument
Tag No
Hygrometer
Code
Serial Number
Invoice Date
Location of Instrument
Tag No
Hygrometer
Code
Serial Number
Invoice Date
Location of Instrument
Tag No
- I.
S.
MDM300 I.S.
Advanced Dew-Point Hygrometer
(for use in hazardous areas)
For Michell Instruments' contact information please go to
www.michell.com
© 2017 Michell Instruments
This document is the property of Michell Instruments Ltd. and may not be copied or
otherwise reproduced, communicated in any way to third parties, nor stored in any Data
Processing System without the express written authorization of Michell Instruments Ltd.
MDM300 I.S. User’s Manual
Contents
Safety ............................................................................................................................... vii
Electrical Safety ......................................................................................................... vii
Pressure Safety ........................................................................................................... vii
Toxic Materials ............................................................................................................ vii
Repair and Maintenance .............................................................................................. vii
Calibration .................................................................................................................. vii
Safety Conformity ....................................................................................................... vii
Abbreviations .................................................................................................................... viii
Warnings .......................................................................................................................... viii
1
2
3
iv
INTRODUCTION ................................................................................................1
1.1
Controls and Indicators ....................................................................................... 3
1.2
Function Keys..................................................................................................... 5
1.2.1
Enter Key ..................................................................................................... 5
1.2.2
Up () and Down () Keys ........................................................................... 5
1.2.3
Right () Key ............................................................................................... 5
1.2.4
Left () / Escape Key.................................................................................... 5
1.3
Instrument Display ............................................................................................. 6
1.3.1
Display Units................................................................................................. 7
1.3.2
Status Display Indications .............................................................................. 8
INSTALLATION ..................................................................................................9
2.1
2.2
2.3
2.4
2.4.1
2.4.2
2.5
2.5.1
2.6
2.6.1
2.6.2
2.7
Safety ................................................................................................................ 9
Unpacking the Instrument ................................................................................... 9
MDM300 I.S. Accessories .................................................................................. 10
Operational Requirements ................................................................................. 12
Environmental Requirements – MDM300 I.S. Instrument................................ 12
Charger Electrical Requirements ................................................................... 12
Instrument Gas Connections ............................................................................. 12
Gas Inlet /Outlet Fittings ............................................................................. 13
Connect External Sensors.................................................................................. 14
Set up External Sensor Interface .................................................................. 15
Entering User Pressure ................................................................................ 15
Battery Charging .............................................................................................. 16
OPERATION ....................................................................................................18
3.1
Preparation for Operation .................................................................................. 18
3.2
Instrument Start-Up ........................................................................................ 19
3.3
Overall Menu Structure and Operation................................................................ 20
3.3.1
SET-UP Menu .............................................................................................. 20
3.3.2
Chart Page ................................................................................................. 20
3.4
SET-UP Menu Parameters .................................................................................. 22
3.4.1
SETTINGS .................................................................................................. 22
3.4.2
LOGGING ................................................................................................... 23
3.4.3
BLUETOOTH ............................................................................................... 24
3.4.3.1
Bluetooth Pairing Procedure ................................................................... 25
3.4.4
EXTERNAL (Sensor Interface) ..................................................................... 26
3.4.5
CLOCK ....................................................................................................... 27
3.4.6
HMI ........................................................................................................... 28
3.4.7
INFO .......................................................................................................... 29
3.4.8
CHART Page ............................................................................................... 29
3.4.9
LOG FILES Page .......................................................................................... 30
3.4.10
LOGS Page ................................................................................................. 30
3.4.11
CALIBRATION ............................................................................................. 31
3.5
Default Parameters ........................................................................................... 32
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
3.6
Guide to Measurement and Sampling ................................................................. 33
3.6.1
Measuring at Atmospheric or System Pressure .............................................. 34
3.6.2
Measurement Guide .................................................................................... 35
3.6.3
Conditional Sensor Purge ............................................................................. 37
3.7
Battery Management ........................................................................................ 37
3.7.1
Battery Troubleshooting ............................................................................... 37
4
5
6
7
GOOD MEASUREMENT PRACTICE .....................................................................38
4.1
Sampling Hints ................................................................................................. 39
APPLICATION SOFTWARE ................................................................................42
CALIBRATION..................................................................................................43
6.1
6.2
6.3
Traceability ...................................................................................................... 43
Calibration Method ........................................................................................... 44
Calibration Correction Method ........................................................................... 45
SHIPPING .......................................................................................................46
Appendices
Appendix A
Appendix B
Appendix C
Appendix D
Appendix E
Appendix F
Technical Specifications .............................................................................. 48
A.1
Dimensions ................................................................................. 49
Datalog Status Display ............................................................................... 51
Hazardous Area Certification ...................................................................... 54
C.1
Product Standards ....................................................................... 54
C.2
Product Certification .................................................................... 54
C.3
Global Certificates/Approvals ........................................................ 54
C.4
Input Terminal Parameters .......................................................... 54
C.5
Special Conditions of Use ............................................................. 55
C.6
Maintenance and Installation ........................................................ 55
FCC Declaration......................................................................................... 57
Quality, Recycling & Warranty Information................................................... 59
Return Document & Decontamination Declaration ........................................ 61
Michell Instruments
v
MDM300 I.S. User’s Manual
Figures
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
34
35
36
37
38
MDM300 I.S. Advanced Dew-Point Hygrometer .............................................2
User Connections, Controls and Indicators....................................................3
Instrument Display .....................................................................................6
Packing Method ..........................................................................................9
Gas Port Adaptors ....................................................................................10
Accessories ..............................................................................................11
Bonded Seal Fitting ..................................................................................13
Gas Coupling Examples for Atmospheric Pressure Measurement...................13
MDM300 I.S. Remote Sensor Interface .......................................................14
External Sensor Connection .......................................................................14
Typical External Dew-Point Display.............................................................15
Battery Charger Connection ......................................................................16
Start-Up Sequence ...................................................................................19
Menu Structure ........................................................................................21
SETTINGS Page ........................................................................................22
LOGGING Page.........................................................................................23
BLUETOOTH Page ....................................................................................24
Typical Bluetooth Pairing Sequence ............................................................25
EXTERNAL SET-UP Page............................................................................26
CLOCK Page .............................................................................................27
HMI Page.................................................................................................28
INFO Page ...............................................................................................29
CHART Page.............................................................................................29
LOG FILES Page .......................................................................................30
LOGS Page...............................................................................................30
CALIBRATION Page ..................................................................................31
Easi-Fit Sample Kit
MDM300 Panel-Mount Sampling System .........33
Large and Small Orifice Fitting ...................................................................34
Typical Application Software Screen ...........................................................42
Typical 7-point Calibration Certificate .........................................................43
Calibration Menu Page ..............................................................................45
Instrument Packing Details........................................................................46
Dimensions - MDM300 I.S. ........................................................................49
Current Datalog File Display ......................................................................51
MDM300 I.S. Status Register .....................................................................51
MDM300 I.S. Status Register (Hex 28) .......................................................51
Tables
Table
Table
Table
Table
Table
Table
Table
Table
Table
Table
Table
Table
Table
vi
1
2
3
4
5
6
7
8
9
10
11
12
13
Controls and Indicators ................................................................................4
Instrument Display Descriptions ...................................................................6
Adaptor Fittings ......................................................................................... 12
SETTINGS Parameters ............................................................................... 22
LOGGING Parameters ................................................................................ 23
BLUETOOTH Parameters ............................................................................ 24
EXTERNAL Sensor Parameters .................................................................... 26
CLOCK Parameters .................................................................................... 27
HMI Parameters ........................................................................................ 28
MDM300 I.S. Default Parameters ................................................................ 32
MDM300 I.S. Measurement Procedures ....................................................... 35
Example Of Calibration Run Readings.......................................................... 44
Status Register Flags ................................................................................. 52
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
Safety
The manufacturer has designed this equipment to be safe when operated using the procedures
detailed in this manual. The user must not use this equipment for any other purpose than that
stated. Do not apply values greater than the maximum value stated.
This manual contains operating and safety instructions, which must be followed to ensure the safe
operation and to maintain the equipment in a safe condition. The safety instructions are either
warnings or cautions issued to protect the user and the equipment from injury or damage. Use
competent personnel using good engineering practice for all procedures in this manual.
Electrical Safety
!
The instrument is designed to be completely safe when used with options and accessories supplied by
the manufacturer for use with the instrument. The instrument is powered by an internally mounted
rechargeable battery - this battery should never be allowed to fully discharge. The input power
supply voltage limits for the battery charger supplied with the instrument are 100 to 240 V AC, 50/60
Hz.
NOTE: No other battery charger unit, other than that supplied with the instrument
should be used.
NOTE: Do not allow the battery to fully discharge.
Pressure Safety
!
DO NOT permit pressures greater than the safe working pressure to be applied to the instrument.
The specified safe working pressure (SWP), for this instrument is 350 barg (5076 psig).
Toxic Materials
!
The use of hazardous materials in the construction of this instrument has been minimized. During
normal operation it is not possible for the user to come into contact with any hazardous substance
which might be employed in the construction of the instrument. Care should, however, be exercised
during maintenance and the disposal of certain parts.
Repair and Maintenance
The instrument must be maintained either by the manufacturer or an accredited service agent. Refer
to www.michell.com for details of Michell Instruments’ worldwide offices contact information.
Calibration
The recommended calibration interval for the MDM300 I.S. is 12 months. The instrument should be
returned to the manufacturer, Michell Instruments Ltd., or one of their accredited service agents for
re-calibration.
Safety Conformity
This product meets the essential protection requirements of the relevant EU directives. Further
details of applied standards may be found in Appendix F.
Michell Instruments
vii
MDM300 I.S. User’s Manual
Abbreviations
The following abbreviations are used in this manual:
AC
atm
barg
bara
°C
°F
K
COM
DC
ft
Hz
kg
lb
Nl/min
m
mA
Mb
max
min
mm
MPa
No.
PIN
ppmV
ppmW
psig
scfh
SWP
sec
V
alternating current
pressure unit (atmosphere)
pressure unit (=100 kP or 0.987 atm) gauge
bar absolute
degrees Celsius
degrees Fahrenheit
Kelvin (absolute temperature)
common
direct current
foot (feet)
Hertz
kilogram(s)
pound
liters per minute
meter(s)
milliampere
megabytes
maximum
minute(s)
millimeter(s)
megapascal
number
personal identification number
parts per million (by volume)
parts per million (by weight)
pounds per square inch
standard cubic feet per hour
safe working pressure
second(s)
volts
Warnings
The following general warning listed below is applicable to this instrument. It is repeated
in the text in the appropriate locations.
Where this hazard warning symbol appears in the following
sections it is used to indicate areas where potentially
hazardous operations need to be carried out.
viii
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
1
INTRODUCTION
INTRODUCTION
The MDM300 I.S. Advanced Dew-Point Hygrometer is a portable instrument designed for online measurement of moisture content in non-corrosive gases in hazardous areas, over
an operational range of -100 to +20°C (-148 to +68°F).
The instrument is independently assessed and certificated as being intrinsically safe and
fully compatible with safe operation within defined Zone 0 hazardous areas.
The instrument is contained within a steel fiber-loaded high-impact polyamide 6 case,
sealed to IP66 / NEMA4 standard and is powered by an internally mounted Nickel
Metal Hydride (NiMH) battery, designed to typically provide 24 hours continuous use
between charges. Continuous battery charge status indication is provided. Additional
battery status information is provided by a battery indicator icon, in addition to a warning
beep and Shutdown Mode.
The MDM300 I.S. is fitted with an internally mounted ceramic sensor, which is enhanced
for a quicker response to dew points as dry as -75°Cdp (-103°Fdp).
The MDM300 I.S. can also be used to read the dew-point signal from a Michell
Instruments’ Easidew I.S. transmitter. To do this, the MDM300 I.S. Remote Sensor
Interface is used to connect to the Easidew I.S. transmitter.
No other sensor can be connected to the MDM300 I.S.
A graphical display presents the dew-point data in large format characters and
simultaneously provides a primary display of real time dew-point readings and a
secondary display, in smaller characters, for the external sensor input. If no external
input is programmed, gas temperature (measured by the internal sensor) is displayed
by default.
A fully programmable, real-time, datalogging facility is provided which has an internal
memory capacity of 8Mb, capable of storing up to 10,000 logs per file (typically giving
a maximum of 64 log files).
A Bluetooth, wireless, communication system is provided, giving access to a dedicated,
PC based, MDM300 I.S. Software Application Package which provides the facility for
handling the logged data files and uploading and downloading instrument parameters.
A user-friendly operator interface provides easy access to all levels of the instrument’s
functionality.
An easy-to-follow calibration routine is built into the instrument’s software.
Michell Instruments
1
MDM300 I.S. User’s Manual
INTRODUCTION
Two versions of the instrument are available, an MDM300 (standard) version and an
MDM300 I.S. (intrinsically safe) version.
This manual covers the MDM300 I.S. version only.
For information about the MDM300 contact your local Michell Instruments’ representative
(contact information at www.michell.com).
- I.
Figure 1
S.
MDM300 I.S. Advanced Dew-Point Hygrometer
(for use in hazardous areas)
2
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
1.1
INTRODUCTION
Controls and Indicators
The controls and indicators associated with the MDM300 I.S. instrument are located on
the front panel of the instrument.
Connections to the MDM300 I.S. dew-point hygrometer, comprising the gas ports,
battery charger input connector and input connector for the external sensor are all made to
the top panel.
Figure 2 shows the layout of these controls and Table 1 describes their respective
operational functions.
2
- I.S.
1
- I.S.
7
Figure 2
Michell Instruments
6
5
4
3
User Connections, Controls and Indicators
3
MDM300 I.S. User’s Manual
INTRODUCTION
Item
Panel
Description
1
Front
Function keys. Refer to Section 1.2 for the details of these
keys.
Instrument display, partitioned to show 3 main panels:
The primary display shows internal sensor parameters.
2
Front
The secondary display indicates the external sensor
parameter.
The status display area shows icons representing battery
charge state, initialization in progress, data logging in
progress, keyboard lock status and keyboard beep status.
3
Top
Instrument ON/OFF switch.
NOTE: The instrument does not need be switched ON
in order to charge the internal NiMH battery.
4
Top
Gas Output port. Refer to Section 2.5.
5
Top
Gas Input port. Refer to Section 2.5.
Analog input connector for external sensor.
By default, this signal is displayed in the secondary display
area but may be configured to be displayed as the primary
display.
6
Top
If no external input is selected, the internal sensor
temperature is shown, on the secondary display, by default
(refer to Section 3.4.6).
NOTE: The hinged rubber protection cover should be
kept closed when the connector is not in use.
Socket for connection of battery charger (located behind
secured cover).
!
7
Top
The secured cover should be kept screwed on when the
connector is not in use.
!
ONLY USE THE CHARGER PROVIDED
!
Never allow the battery to fully discharge
Table 1
4
Connection to the battery charger should
always be made in a safe area - never in a
hazardous area environment
Controls and Indicators
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
1.2
INTRODUCTION
Function Keys
The function keys, located on the front panel, are used to select operations from the
menus and to select and enter parameter variables within those menu levels.
The function key described is shaded darker and the operation of the keys is as follows:
1.2.1
Enter Key
The Enter key is used within the menus to highlight and select
options and to accept entered values.
Operation of this key from the Main Display causes the Passcode
entry page (for entry to the SET-UP Menu) to be displayed.
1.2.2
Up () and Down () Keys
Within the SET-UP Menu and sub-menus these  and  keys are
used to scroll down and highlight options.
Within sub-menu levels requiring the entry of alpha numeric values,
these keys are used to change the values. Pressing the key once
increases or decreases the selected field by one step. Pressing and
holding the key will cause the selected field to be continuously
increased or decreased until the key is released.
1.2.3
Right () Key
Within sub-menu levels requiring the entry of alpha numeric
values, this  key is used to shift the insertion point right in the
file name entry field.
From the Main Display, pressing this  key moves to the Chart
Page.
From the Chart Page, pressing this  key moves to the Logging
Pages.
1.2.4
Left () / Escape Key
Within sub-menu levels requiring the entry of alpha numeric values,
this  key is used to shift the insertion point left in the file name
entry field. As the insertion point is shifted to the left, the entry at
the former position is deleted.
Within any menu or sub-menu level, pressing this  key escapes
to the previous menu above the current level.
Michell Instruments
5
MDM300 I.S. User’s Manual
INTRODUCTION
1.3
Instrument Display
The graphics display and the associated function keypad (Figure 2), form the operator
interface of the equipment. Figure 3 shows all the elements of a typical display page
after the instrument’s initialization period has completed.
Table 2 details the elements of the display:
Dewpoint
Internal
6.9
12.7
°C
°C Temp.
Measurement in progress
8
Figure 3
Item
1
2
3
4
5
6
7
8
6
5
4
3
2
1
Instrument Display
Description
Secondary display
Shows reading from external sensor, if configured; or internal temperature if
external sensor is not configured (refer to Section 3.4.6).
Battery charge indicator icon
Flashes when the battery needs charging. A warning beep sounds when the
battery charge level is critical - followed immediately by Shutdown Mode.
NOTE: The icon becomes animated when the charger is connected.
Keyboard beep indicator
Indicates that the keyboard beep is switched on.
Keyboard lock indicator
Indicates that the keyboard is locked.
Datalog status indicator
Indicates that logging is enabled and running.
Sensor initializing indicator
Indicates that the initialization process is in progress and that the sensor heating
is on. The presence of this symbol is accompanied by Initializing internal sensor
status message.
Primary display
During normal operation, the internal sensor readings are shown in the
primary display. If the external sensor has been configured then this reading
can be shown in this display (refer to Section 3.4.6).
Status message display area
Displays status and error messages.
Table 2
6
7
Instrument Display Descriptions
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
1.3.1
INTRODUCTION
Display Units
The instrument can display the measured reading in the following units:
Absolute Humidity
•
•
•
lb/MMscf
g/m3
g/m3 NG
Moisture Content
•
•
•
ppmV NG
ppmV
ppmW (AIR, USER, H2, SF6, CO2 or N2)
Dew Point
•
•
•
°C
°F
K
Relative Humidity (%)
Mixing Ratio
•
g/kg (AIR, USER, H2, SF6, CO2 or N2)
To toggle between displayed units, press either the  or  key.
Michell Instruments
7
MDM300 I.S. User’s Manual
INTRODUCTION
1.3.2
Status Display Indications
‘Initializing Internal Sensor’
This is displayed immediately after the instrument has been powered up, and indicates
that the sensor is being heated up to accelerate equilibrium with the moisture in the
sample gas. This has the effect of drying the sensor out, and results in the ‘undershoot’
seen in the first stage of the measurement process.
‘Measurement in Progress’
This is displayed after the sensor initialization has finished, and indicates that the
sensor is running through the following initial measurement procedure:
1.
Undershooting the dew-point
2.
Making a first estimate
3.
Running a QRA (Quick Response Algorithm), if necessary
Once the message has disappeared, this indicates that the instrument has finished its
accelerated approach to the actual dew point. Depending on the conditions, it may
continue to respond for a number of minutes more, before settling on (or tracking) the
actual measured dew point.
Other Status Display Indications
Internal sensor
error
Dew-point reading out of range (> +30 / < -120°C)
Sensor internal temperature reading out of range (> +100 /
Internal thermistor < -40°C) or
error
Thermistor fault
External sensor
error
Battery low
Battery
low
recharge now
Log finished
External Sensor Input out of range (< 4 mA / > 20 mA)
Battery level low - recharge as soon as possible
-
Battery level critical - recharge immediately
Log file has reached the maximum of 10,000 logs and logging has
been stopped
Internal sensor not Could not detect internal sensor on power up
found
Default CONFIG file Config. file missing, new file created and default settings used
used
8
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
2
INSTALLATION
2.1
Safety
!
2.2
INSTALLATION
It is essential that the installation of the electrical and
gas supplies to this instrument be undertaken by qualified
personnel.
Unpacking the Instrument
- I.S
4
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The MDM300 I.S. instrument is packed into a standard box and the method of unpacking
is shown below:
-I
.S
.
2
1
Figure 4
Packing Method
1.
Open the box (1) and unpack carefully.
2.
Remove the MDM300 I.S. (2), the user’s manual (3) and the accessories
box (4).
3.
Save all the packing materials for the purpose of returning the instrument
for re-calibration or any warranty claims.
4.
If the optional carry bag has been ordered it will be located underneath
the foam insert, in a cardboard box.
Michell Instruments
9
MDM300 I.S. User’s Manual
INSTALLATION
2.3
MDM300 I.S. Accessories
The accessories for the MDM300 I.S. are shown in Figure 6. Items 1 to 7 are supplied
as standard and item 8 is optional. Please check that all the standard components are
present after unpacking. Report any shortages immediately.
1.
Calibration certificate
2.
User’s manual
3.
Charger unit
4.
Country specific mains lead
5.
Gas Input/Output port adaptors
(three provided - two fitted to the instrument - see Figure 5)
6.
Application Software CD
7.
Quick-start card
8.
Carrying case - made from anti-static materials suitable for use in
hazardous areas (optional)
Three gas port adaptors are provided, two with a large bore orifice and one with a
small bore orifice. Depending upon configuration, this permits the instrument to be
run at either system pressure or atmospheric pressure and facilitates the connection of
external flow monitoring and control.
NOTE: On delivery the two large orifice adaptors are fitted into the instrument’s
gas ports (1 and 2) as shown in Figure 5. One small orifice adaptor is provided
as a loose spare in the accessory pack (see Section 2.5).
- I.S.
Small orifice
Large orifice
2
Gas In
1
Gas Out
Figure 5
10
Gas Port Adaptors
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
INSTALLATION
2
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Us w-P 00 I
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97
21
Ju 3 Issu
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20 e 4.1
13
- I.S
MDM300 & MDM300 I.S. Quick Start Guide
Connect the MDM to
the sample gas stream
Determine the approximate
dew point by using the ‘initial check’
procedure on the reverse
Typical MDM300 Sampling Arrangement
SAMPLE FLOW
Is the
equivalent
dew point
> - 40Cdp?
1
Yes
2
Adjust the flow rate
using the
outlet flow control
valve to
between
0.2 and 0.5 l/min
System
No
Atmospheric
Do you
want to measure
at Atmospheric pressure
or System
pressure?
Do you
want to measure
at Atmospheric pressure
or System
pressure?
3
System
Adjust the flow rate
using the
inlet flow control valve
to
between
0.2 and 0.5 l/min
Atmospheric
3
Turn the instrument
on. The status display
will read
‘Initializing
internal sensor’
Adjust the flow rate
using the
inlet flow control valve
to
between
0.2 and 0.5 l/min
Turn the instrument
on. The status display
will read
‘Initializing
internal sensor’
After the initialization
period is complete,
close the outlet flow
4
Turn the instrument on.
The status display will read
‘Initializing internal sensor’.
control valve 4 and
fully open the inlet
flow control valve 3 .
Then adjust the flow
rate using the outlet
flow control valve
The instrument will begin
Measurement mode. During the first few
to between 0.2 and
0.5 l/min.
minutes of this, the displayed moisture
4
value will drop rapidly below the actual
moisture value, before returning
VENT
to a stable reading.
1 Coalescing Filter
2 Particulate Filter
3 Inlet Flow Control Valve
The instrument’s display will show an initial
measured value, and the status display
will show ‘Measurement in progress’.
4 Outlet Flow Control Valve
Once ‘Measurement in progress’
has disappeared, the instrument is close
to the final dew point.
Depending on the conditions, it may
continue to respond for a number of
minutes before tracking the measured dew point.
!
HIGH PRESSURE! High pressure gases are potentially hazardous. Energy stored in these
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97244 Issue 02, July 2011
7
5
6
8
Figure 6
Michell Instruments
Accessories
11
MDM300 I.S. User’s Manual
INSTALLATION
2.4
Operational Requirements
Operational requirements are as follows:
2.4.1
2.4.2
Sample gas flow rate:
0.2 to 0.5 Nl/min (0.5 to 1 scfh)
Operating pressure:
0 to 350 barg (0 to 5076 psig)
Environmental Requirements – MDM300 I.S. Instrument
Operating temperature range:
-20 to +50°C (-4 to +122°F)
Humidity:
0 to 100% RH (non-condensing)
Altitude:
Up to 2000m (6562 ft)
Charger Electrical Requirements
Charger supply voltage:
2.5
100 to 240 V AC (+10%, -15%)
50/60 Hz (±5%), 8 VA
Instrument Gas Connections
!
POSSIBLE INJURY! The tubing, valves and other apparatus
attached to this instrument must be adequate for the
maximum pressure which will be applied, otherwise physical
injury to the operator or bystander is possible.
Sample gas connections are made via the Gas In (2) and Gas Out (1) ports located on
the rear of the instrument as shown in Figure 5.
The MDM300 I.S. is supplied with a large bore orifice fitting installed into the Gas In
and Gas Out ports. These fittings have an 1/8” NPT female thread to allow the user to
connect other components of their choice.
Atmospheric pressure or system pressure dew point can be measured depending on the
configuration of the adaptor fittings as shown in Table 3.
For gas pressures outside the range 2.5 to 10 barg, the instrument requires external
flow control components, as shown in Figure 8.
Dew point at
Gas Inlet port
fitting
Gas Outlet port
fitting
Atmospheric
Small bore orifice
Large bore orifice
System
Large bore orifice
Small bore orifice
Either (using
other flow control
components)
Large bore orifice
Large bore orifice
Table 3
12
Sample gas
pressure
2.5 to 10 barg
(36 to 145 psig)
2.5 to 10 barg
(36 to 145 psig)
0 to 350 barg
(0 to 5076 psig)
Adaptor Fittings
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
2.5.1
INSTALLATION
Gas Inlet /Outlet Fittings
HIGH PRESSURE! High pressure gases are potentially
hazardous. Energy stored in these gases can be released
suddenly and with extreme force. High pressure systems
should be assembled and operated only by people who have
been trained in proper safety practices.
!
Before making a measurement, the gas fittings should be attached to the instrument as
shown in Table 3.
1.
Fit the required orifice fittings with supplied bonded seals. Ensure bonded
seals are correctly seated in recessed grooves.
PTFE tape here
Adaptor
h
h
h
1/8” Swagelok
fitting h
Figure 7
Bonded seal
Bonded Seal Fitting
2.
Fit any other adaptors that might be required.
3.
If the small bore orifice fitting is not being utilized then one of the optional
application kits could be fitted (as shown below).
I.S.
Figure 8
Gas Coupling Examples for Atmospheric Pressure Measurement
NOTE: The application kit shown above (excluding the orifice fittings) is not
supplied as standard, but is part of a range of kits which can be ordered from
Michell Instruments, on request.
NOTE: The bonded seals used for the MDM300 I.S. are Dowty part number
400-228-4490-74 (from Michell Instruments, part number MDM300-DS).
Michell Instruments
13
MDM300 I.S. User’s Manual
INSTALLATION
2.6
Connect External Sensors
The MDM300 I.S. can be configured for connection to a Michell Instruments’ Easidew
I.S. transmitter (ATEX Baseefa 06ATEX0330X, IECEx BAS06.0090X), via the MDM300
I.S. Remote Sensor Interface, when the Easidew I.S. transmitter is installed within a
hazardous area.
The MDM300 I.S. Remote Sensor Interface is a passive device. The combined terminal
parameters of the MDM300 I.S. and of the barrier used with the Easidew I.S. system
must not exceed the input terminal parameters of the Easidew I.S. as specified in the
System Drawing (System Certificate No. Baseefa 07Y0027).
Figure 9


Connect to
Connect to Easidew I.S. Sensor


MDM300 I.S.
REMOTE SENSOR INTERFACE

Connect to
MDM300 I.S.

EASIDEW I.S. SYSTEM
To view any of these certificates go to: http://www.michell.com
MDM300 I.S. Remote Sensor Interface
Refer to Appendix C (Hazardous Area Certification) for the MDM300 I.S. terminal
parameters.
Figure 10 shows the connection of the MDM300 I.S. Remote Sensor Interface to the
MDM300 I.S. and the Easidew I.S. transmitter.
W
W
Connect to
MDM300 I.S.
REMOTE SENSOR INTERFACE
Connect to Easidew I.S. Sensor
W
W
W
W
Connect to
MDM300 I.S.
REMOTE SENSOR
h
INTERFACE
EASIDEW I.S. SYSTEM
HAZARDOUS AREA X
X SAFE AREA
EASIDEW I.S. SENSOR
BARRIER ASSEMBLY
Safe Ex ia Class 1, Division 1, Group A,B,
Entity Ex90385
Terminal
Ui = 28V
Ii = 93mA
Pi = 651m
Ci = 37nF
20mA 0Hz 28Vdc Li = 0
E416-051
Baseefa06ATEX0330X
IECEx BAS 06.0090X
Ex ia IIC T4 -20C to +60C
EASIDEW I.S. Dew Point Tran
www.michell.com
h
,5 Nm Ely, Cambs UK
X
S.
X
EASIDEW I.S.
h
- I.
SYSTEM CERT
Baseefa 07Y0027
MDM300 I.S.
Figure 10 External Sensor Connection
14
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
2.6.1
INSTALLATION
Set up External Sensor Interface
After connecting the Easidew I.S. transmitter, the following parameters must be defined:
Switch on the instrument and set the required DP/TEMP units to either °C, °F or K from
the SETTINGS Menu (refer to Section 3.4.1). Set up the required pressure units.
Using the EXTERNAL option from the SET-UP Menu, set up the instrument for an
external Easidew input as follows (refer to Section 3.4.4):
EXTERNAL TYPE
Select EASIDEW
EXTERNAL ZERO
-100°C (DP Temp represented by 4 mA input - can be reset)
EXTERNAL SPAN
20°C (DP Temp represented by 20 mA input - can be reset)
USER PRESSURE
Refer to Section 2.6.2. NOTE: Pressure compensation does not
affect the reading of the external sensor.
After completion of the above settings, return to the Main Display. The instrument will
now display dew point from the external sensor in the secondary display area and the
selected units. (Refer to Section 3.4.6 for more information.)
An example is shown below:
Dewpoint
-26.9
External
°C
-25.7
°C dp
Figure 11 Typical External Dew-Point Display
2.6.2
Entering User Pressure
The MDM300 I.S. can be programmed with a pressure to be used in the calculation of
atmospheric equivalent or pressure dew point, moisture content or absolute humidity.
NOTE: Care should be taken to ensure that the entered pressure is correct as
it may have a considerable effect on the measurement.
Using the EXTERNAL option in the SET-UP Menu, set a user pressure as follows.
1.
Scroll to USER PRESSURE.
2.
Use the  and  keys to select either ATM (for atmospheric pressure) or
the required pressure.
NOTE: The pressure units are selected in the Settings Menu.
Michell Instruments
15
MDM300 I.S. User’s Manual
INSTALLATION
2.7
Battery Charging
!
WARNING: The battery charger must NOT be connected within
the hazardous area.
The battery charger socket cover MUST be closed when the
product is in use within a hazardous area.
The MDM300 I.S. is powered from an internally mounted, rechargeable Nickel Metal
Hydride (NiMH) battery. Typically, depending upon the instrument settings, the battery
will provide approximately 24 hours of continuous operation when fully charged.
A graphical display of battery charge state is provided and an audible warning is given
as the battery approaches full discharge.
Loosen the securing screw and swing aside the sealing cover (2). Insert the battery
charger connector (1) into the charger connector as shown in Figure 12.
- I.S.
1
2
Figure 12 Battery Charger Connection
Connect an AC power supply, 100 to 240 V AC, 50/60 Hz, to the battery charger unit.
NOTE: The MDM300 I.S. instrument does not need to be switched on in order
to charge the battery.
16
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
INSTALLATION
The battery charger supplied is a ‘Smart’ charger.
!
WARNING: DO NOT use any other charger than that supplied
with this product.
The use of any charger other than that supplied for use will
invalidate the product warranty.
The smart charger goes through three charging stages:
•
pre-charge
•
fast-charge
•
trickle charge
If the battery has been damaged then the charger will not begin the fast-charge stage.
Please contact Michell Instruments’ service department for advice.
Once the charger has finished the fast-charge stage it can be safely disconnected.
Switch off the AC power supply, remove the charger unit and close the instrument’s
charge connector protection cover.
A complete charge cycle will take 2 to 4 hours for a fully discharged battery.
The table below shows the different charging stages and durations.
Pre-charge
Rapid-charge
FW 7219 Type
(Older)
Flashes Orange
Flashes Green (Fast)
Trickle-charge
Flashes Green (Slow)
Charging
complete
Green
Stage / Charger
FW 7219
Michell Instruments
Cell-con
(Newer)
Orange
Red
Green, flashes
Orange
Up to 5 minutes
2 to 4 hours
Indefinite - Cell-con
One hour - FW
Green
N/A
Duration
Cell-con
17
MDM300 I.S. User’s Manual
OPERATION
3
OPERATION
High pressure gases are potentially dangerous.
!
3.1
POSSIBLE INJURY! The tubing, valves and other apparatus
attached to this instrument must be adequate for the
maximum pressure which will be applied, otherwise physical
injury to the operator or bystander is possible.
Preparation for Operation
The MDM300 I.S. has a user-friendly system of operation. Before operation it is
recommended that the user becomes familiar with Section 1 of this manual in which
the equipment controls and indicators, and the elements of the display are described.
Prior to making a measurement, the instrument must have been connected to a sample
gas stream, see Section 2.5.
It is recommended that the battery is charged before conducting any tests (refer to
Section 3.7).
The instrument will have been set up with a number of factory default parameters.
These default parameters are shown in Table 10, together with a reference to the
relevant part of this manual which details the method of changing these default values.
18
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
3.2
OPERATION
Instrument Start-Up
At switch on, the instrument goes through an
initialization process of between 4 and 7 minutes,
depending on the sensor and sample gas
characteristics. During this time the internal sensor is
heated to a maximum of +60°C (+140°F). The heating
process increases the mobility of water molecules and
accelerates equilibrium with the passing sample gas.
During this period the sample gas flow purges the
system. After this period, the sensor will be dried to
below the dew point of the gas to be measured. The
heating is then switched off and the display becomes
dynamic. Figure 13 shows a typical start-up sequence.
At switch-on, the System Initializing Page is displayed
for several minutes during which the page will show a
countdown of the remaining initialization time. NOTE:
The initialization stage is skipped if the initial
dew point is detected to be within 2°C of the
dew point when the instrument was switched
off.
MDM300 I.S.
System Initializing
Internal
Initializing: 04:32
60.0
°C Temp.
Initializing internal sensor
Dewpoint
ppmv
19.216
10.3 °C
Internal
22.3
°C Temp.
Measurement in progress
Dewpoint
9.1
Internal
°C
22.3
°C Temp.
Figure 13 Start-Up Sequence
During this period, gas will be flowing through the
sensor and can be externally regulated to meet the
instrument’s flow requirements, and the real time
sensor temperature is indicated in the secondary
display area. The initializing icon (item 6 in Figure 3)
is displayed in the status area and the keyboard is
locked out until the initialization period has expired.
It is possible to terminate the initialization process before the initialization period
has timed out by pressing the  and  keys simultaneously. This action aborts the
instrument’s response enhancement system and allows the operator to make an
immediate measurement if the measured dew point is wetter than -20°Cdp (-4°Fdp).
While the initialization process is in progress, the backlight time-out is inhibited and, if
any external sensor has been configured and connected to the instrument, display of
the external sensor reading is also inhibited.
After the end of the initialization period, the display reverts to Measurement Mode
displaying dew point (in the currently selected unit) in the primary display area, and any
external sensor reading in the secondary display area. By default, the internal temperature is
displayed in the secondary display area if no external sensor is configured.
If an external sensor has been selected but has either not been connected or is giving
an over-range indication, a flashing External Sensor Error message (alternating with a
Measurement in progress message) will be displayed.
While the Quick Response Algorithm is in operation a Measurement in progress
message is displayed. After this, depending on the sample conditions, the instrument
may continue to respond to the final dew-point for a number of minutes. This is further
explained in Section 3.6.
Michell Instruments
19
OPERATION
3.3
Overall Menu Structure and Operation
3.3.1
SET-UP Menu
MDM300 I.S. User’s Manual
All instrument settings are made from the SET-UP Menu which is accessible from the
Main Display by pressing the Enter key.
On the first occasion after switch-on the Passcode Entry page will be displayed. Enter
the passcode 7316 as follows:
•
With the first digit of the passcode highlighted, enter the first digit (7)
using the  and  keys.
•
Press the Enter key to accept this entry and move to the next digit
position.
•
Repeat this procedure until all the passcode digits have been entered.
On successful entry of the last digit, the SET-UP Menu will be displayed.
NOTE: If the passcode is incorrectly entered, the passcode page remains displayed
showing the entries that have been made. To accept any digit as correct and to move
to the next digit position, press the Enter key. Change the incorrect entry, using the 
or  keys, and when the correct passcode has been entered, the SET-UP Menu will be
displayed.
Within this SET-UP Menu, eight options are available: SETTINGS, LOGGING, BLUETOOTH,
EXTERNAL, CLOCK, HMI, CALIBRATION and INFO. For more detailed information on
these options refer to Section 3.4.
These options are selected by means of the  and  keys. Pressing the Enter key then
provides access to a sub-menu which permits the variables associated with that option
to be edited, as follows:
•
Press the  and  keys to highlight the required field.
•
Press the Enter key to select the field.
•
Press the  and  keys to edit the parameter value associated with
that field.
•
Press the Enter key to enter the new value.
Quit the sub-menu by pressing the  key and return to the SET-UP Menu. From the
SET-UP Menu either select another sub-menu with the  key or press the  key to
return to the Main Display.
3.3.2
Chart Page
The Chart Page is reached from the Main Display, by pressing the  key. The chart
interval is set up under the SETTINGS Menu. For more information on the Chart Page
refer to Section 3.4.8.
Pressing the  key when the chart is displayed will show either the Log Files (if Logging
is not selected), or the current data Logs Page (if Logging is selected). If Logging is
not selected press the Enter key for a shortcut to the LOGGING Menu.
Where more than one page of data is available, the  and  keys are used to scroll
up or down.
20
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
OPERATION
Scroll Unit
to view
Files Page
NO
Main Display (Primary,
Secondary and Status
Windows)
Chart Page
(only if internal sensor
available)
LOGGING?
YES
Logs Page
PASSCODE FOR
SETUP (on start-up
only)
=7316
NO
Scroll to
Adjust Digit
Chart Reset Page
PASSCODE
OK
To toggle
Scroll
selection of
menu items
item
and edit
To return to
previous screen
SET-UP
Menu
PRIMARY DP AT
DP/TEMP UNIT
PRESSURE UNIT
SETTINGS
LOGGING
BLUETOOTH
EXTERNAL
GAS TYPE
MOL WEIGHT
CHART INTERVAL
CLOCK
HMI
CALIBRATION
INFO
Scroll
menu
items
FILE NAME
PARAMETER
LOG INTERVAL
START?
Scroll to
adjust digit
To select
item
PASSCODE FOR CAL
ENABLE
NAME
=4876
NO
EXTERNAL TYPE
EXTERNAL ZERO
EXTERNAL SPAN
USER PRESSURE
PASSCODE
OK?
YEAR
MONTH
DAY
HOUR
MIN
YES
CONTRAST
BRIGHTNESS
KEY TONE
BL TIMEOUT
LANGUAGE
PRIMARY DISP
POINT
REF
MDM300
INFO PAGE
LEGEND
Enter Key
Up/Down Keys
Left Right Keys
Figure 14 Menu Structure
Michell Instruments
21
MDM300 I.S. User’s Manual
OPERATION
3.4
SET-UP Menu Parameters
Follow the instructions in Section 3.3.1 to select the required parameters.
3.4.1
SETTINGS
PRIMARY DP AT
DP/TEMP UNIT
PRESSURE UNIT
GAS TYPE
MOL WEIGHT
CHART INTERVAL
ATMOS
°C
Psig
AIR
N/A
5
SETTINGS
s
Figure 15 SETTINGS Page
Parameter
PRIMARY DP AT
DP/TEMP UNIT
PRESSURE UNIT
GAS TYPE
MOL WEIGHT
CHART INTERVAL
Description
Indicates if the primary display sensor is at atmospheric or system
pressure.
Available Input: ATMOS or PRESS (Atmospheric or Pressure)
Sets system temperature units.
Available Input: °C, K, °F
Sets system pressure units.
Available Input: psig, MPa, psia, bara, KPa, barg,
Defines the sample gas type.
NOTE: The MOL WEIGHT field automatically reads N/A for all
gases other than USER.
For any other type of sample gas, the molecular weight of the gas
must be defined in the MOL WEIGHT field.
Available Input: Air, USER, H2, SF6, CO2, N2
Sets molecular weight of user-defined sample gas, default value 1.
Available Input: Range 1 to 99
Sets chart time interval, default value 5.
Available Input: Range 1 to 60 seconds
Table 4
22
SETTINGS Parameters
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
3.4.2
OPERATION
LOGGING
Logging can be set up either from the SETTINGS Menu or from the Chart Page (see
Section 3.4.8). Both methods of entry lead to the same LOGGING SET-UP menu as
shown below:
>
DEWP
5
s
STOPPED
FILE NAME
PARAMETER
LOG INTERVAL
START?
LOGGING
Figure 16 LOGGING Page
Parameter
FILE NAME
PARAMETER
Description
Defines datalog file name. Field width up to eight alphanumeric
characters.
NOTE:  key deletes characters
NOTE: If a file name is not entered, a logging cycle cannot
be started.
Available Input: 0 - 9, A - Z (keying up and down will change the
numbers to letters or vice-versa)
Sets parameter to be logged. This need not necessarily be the same
as that displayed on the Main Display.
NOTE: Only one parameter may be logged at one time
Available Input: DEWP, GM3, GKG, RH, PPMW, PPMV, CALC DP,
GM3(NG), LBMMSCF, PPMV(NG)
LOG INTERVAL
START ?
Sets log interval in 5 sec increments.
Available Input: Range 5 to 600 seconds
Starts the log cycle after logging parameters are set-up.
NOTE: If a file name is not entered, a logging cycle cannot
be started.
Once logging has started, log file parameter fields are locked out and
cannot be changed.
Available Input: STOPPED, STARTED
Table 5
LOGGING Parameters
NOTE: If a duplicate file name has been entered an error message will be
shown when attempting to start logging.
A maximum of 64 log files can be stored in the instrument memory before
it is necessary to download or remove them. The START ? option will not be
available if this limit is exceeded.
Cycling power will stop the logging.
The size of any one log file is limited to 60kb. If the unit is left logging,
and the file size exceeds 60kb, then the log file will finish automatically. To
ensure that the log file you initiate collects all the data from your test, an
Michell Instruments
23
MDM300 I.S. User’s Manual
OPERATION
appropriate sample time should be chosen. The table below can be used as a
rough guide:
Sample time (sec)
5
10
30
60
100
200
400
600
3.4.3
Logging duration
3 hours
6 hours
18 hours
36 hours
60 hours
120 hours
240 hours
360 hours
BLUETOOTH
Bluetooth mode is used, in conjunction with a dedicated MDM300 I.S. application software
package, for the purpose of uploading datalog files to a PC using a wireless connection. Within
the PC the dedicated Michell application software package is used to upload the files to
the PC’s desktop, from where they can be loaded into other programs, e.g. Microsoft
Excel, for further examination and processing.
ENABLE
NAME
NO
MDM300
BLUETOOTH
Figure 17 BLUETOOTH Page
Parameter
ENABLE
NAME
Description
Turns the Bluetooth facility on or off.
When Bluetooth is turned ON - a status message *in
Bluetooth mode* will be displayed. No other menu options
can be selected at this time and this page remains until the
Bluetooth mode is cancelled by pressing the  key.
Available Input: ON or OFF
Before enabling Bluetooth (above) set up a Bluetooth name (address)
for the instrument. Maximum eight alphanumeric characters. Default
name set is MDM300.
Available Input: 0 - 9, A - Z (keying up and down will change the
numbers to letters or vice-versa)
Table 6
24
BLUETOOTH Parameters
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
OPERATION
3.4.3.1 Bluetooth Pairing Procedure
When the instrument is in Bluetooth mode, a pairing procedure needs to be carried
out in order for the PC system to recognize the instrument. This procedure only needs to be
carried out once for each instrument. A typical pairing procedure is outlined in Figure 18. The
procedure is as follows:
1.
From the PC’s Bluetooth menu, search for devices in range. This yields
the instrument named, i.e. MDM300.
2.
Double click the instrument icon and enter the instrument’s pairing
passcode (7316) for all MDM300 I.S. instruments. NOTE: Each digit
will be shown only briefly as it is entered and then hidden.
3.
When all digits have been entered click Next.
4.
With the serial link established, click Configure. NOTE: The name of
the COM port allocated, i.e. COM7, will need to be entered when
starting the Michell application software.
(7) (3) (1) (6)
Figure 18 Typical Bluetooth Pairing Sequence
Michell Instruments
25
MDM300 I.S. User’s Manual
OPERATION
3.4.4
EXTERNAL (Sensor Interface)
!
The MDM300 I.S. is designed to be connected ONLY to a
Michell Instruments’ remotely mounted Easidew I.S. or
Easidew PRO I.S. transmitter. Connection to any other type of
sensor could impair safety.
The Easidew I.S. or Easidew PRO I.S. must be connected
retaining the associated I.S. barriers and using a Michell
Remote Sensor Interface module. See Section 2.6.
EXTERNAL TYPE
EXTERNAL ZERO
EXTERNAL SPAN
USER PRESSURE
NONE
N/A
N/A
ATM
EXTERNAL
Psig
Figure 19 EXTERNAL SET-UP Page
Parameter
EXTERNAL TYPE
EXTERNAL ZERO
EXTERNAL SPAN
USER PRESSURE
Description
Defines use of Easidew I.S. transmitter.
NOTE: The ZERO and SPAN limits are automatically added
for this transmitter.
Available Input: NONE, EASIDEW
Defines external zero (lower limit).
The ZERO default limit is pre-programmed but can be redefined.
Available Input: Range: -120 to +30°C
Defines external span (upper limit).
The SPAN default limit is pre-programmed but can be redefined.
Available Input: Range: -120 to +30°C
Used in the calculation of dew point at pressure, moisture content
and absolute humidity. If a user pressure is not selected then the
MDM300 I.S. assumes atmospheric pressure. (Refer to Section 2.6.2.)
NOTE: Pressure compensation does not affect the reading
of the external sensor.
Available Input: Range ATM, 0 to 300 barg (or equivalent in other
units).
Table 7
26
EXTERNAL Sensor Parameters
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
3.4.5
OPERATION
CLOCK
YEAR
MONTH
DAY
HOUR
MIN
11
03
26
09
32
CLOCK
Figure 20 CLOCK Page
Parameter
YEAR
MONTH
DAY
HOUR
MIN
Description
Current year
Available Input:
Current month
Available Input:
Current day
Available Input:
Current hour
Available Input:
Current minute
Available Input:
Range: 00 to 99
Range: 01 to 12
Range: 01 to 31
Range: 00 to 23
Range: 00 to 59
Table 8
Michell Instruments
CLOCK Parameters
27
MDM300 I.S. User’s Manual
OPERATION
3.4.6
HMI
CONTRAST
BRIGHTNESS
KEY TONE
BL TIMEOUT
LANGUAGE
PRIMARY DISP
80
75
ON
30
ENG
INTERN
%
%
HMI
s
Figure 21 HMI Page
Parameter
CONTRAST
BRIGHTNESS
KEY TONE
BL TIME-OUT
LANGUAGE
PRIMARY DISP
Description
Sets the contrast on the screen.
Available Input: Range: 0 to 100% in 5% increments
Sets the brightness of the screen.
Available Input: Range: 0 to 100% in 5% increments
Turns the key tone on or off.
Available Input: ON, OFF
Backlight control.
Available Input: OFF, 15 to 60 sec in 15 sec increments
Sets the language required.
Available Input: ENG, DEU, ESP, FRA, ITA, POR
Sets the display option.
NOTE: This option is only accessible if an external sensor has
been configured - see below.
Available Input: INTERN, EXTERN
Table 9
HMI Parameters
If no external input is selected, the internal sensor temperature is shown, on the
secondary display, by default.
When an Easidew I.S. transmitter has been configured, the primary and secondary
displays can be interchanged to show the external sensor reading as the main display
and the internal sensor reading as the secondary display.
With an Easidew I.S. transmitter connected, the ability to display the output of the
external device as the main (large character) display can be particularly advantageous
for a number of applications such as:
28
•
Remote monitoring
•
Calibration checks on an existing installation
•
High pressure measurements
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
3.4.7
OPERATION
INFO
MDM300 I.S. Portable Hygrometer
Firmware 36176 Ver
Sensor serial number
Sensor next cal due
Sensor hours used
www.michell.com
0.01
E050-035
03/09/12
20 hr
Figure 22 INFO Page
This page contains system information and no changes can be made.
Information available:
3.4.8
•
Firmware number and version
•
Sensor serial number
•
Date of sensor calibration next due
•
Hours that the sensor has been used
CHART Page
At any time while the Main Display is indicating internal sensor parameters, a graphical
display of the output can be obtained by pressing the  key from the Main Display.
The chart can be reset at any time by pressing the Enter key. Reset the chart by
pressing the  key or return to the chart, without resetting, by pressing the  key.
A typical chart plot is shown below:
Val
Min
Max
70
55.6
55.3
68.7
%RH
50
t-5
Minutes
t
Figure 23 CHART Page
The X-axis (time) has a default range of 5 minutes and the graph is incremented
(drawn) at the interval set up under the SETTINGS Menu (see Section 3.4.1). The Y-axis
shows the measured value, with respect to time.
The current, maximum and minimum values of the displayed parameter are shown to
the right of the graph and the unit of the selected parameter is displayed below.
Michell Instruments
29
MDM300 I.S. User’s Manual
OPERATION
3.4.9
LOG FILES Page
If the instrument is not logging, pressing the  key, while the chart is displayed, will
show the FILES Page. This page provides a list of all the previously saved log files,
together with an indication of the available memory capacity (see Figure 24). To scroll
through the list, use the  and  keys as required.
1.txt
2.txt
3.txt
4.txt
1K
1K
15K
4K
0130
0130
0305
0315
1318  11 files
169K used
1319
8397K Free
1352
1738 
Not logging, press ENTER to setup logging
Figure 24 LOG FILES Page
The content of the datalog files cannot be examined but, by enabling the instrument’s
Bluetooth mode, (see Section 3.4.3), the MDM300 I.S. application software may be
used to upload the datalog files to a PC.
In the FILES Page a shortcut to the LOGGING Set-Up Menu is provided by pressing the
Enter key. Refer to Section 3.4.2 for logging set-up details.
3.4.10 LOGS Page
If the instrument is logging, pressing the  key, while the chart is displayed, will show
the LOGS Page. The page shows the current log file.
In the LOGS Page a shortcut to the LOGGING Set-Up Menu is provided by pressing the
Enter key. Refer to Section 3.4.2 for logging set-up details.
The  and  keys are both active while the log file is being displayed. To view log
points taken earlier in the logging cycle, press the  key. To continuously scroll back,
keep the  key pressed down.
Similarly, to move forward in the list press the  key, once for a single step, or press
and hold to continuously scroll forward.
#
106
107
108
109
110
INT EXT
26.8 -100.0
26.2
-90.0
-80.0
25.9
-70.0
25.8
25.5
-60.0
ST
0028
0028
0028
0028
0028
File
INT
EXT.
INTVAL
D#
T#
CR030911
RH
EXT_DP
05 Sec
110903
123606
Figure 25 LOGS Page
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MDM300 I.S. User’s Manual
OPERATION
The display shows:
#
INT
EXT
ST
Indicates a log number for each set of log points
Value of primary display parameter
Value of secondary display parameter
Status column which reports the status of the instrument at each log
point in hexadecimal code.
The status codes are explained in Appendix B.
•
FILE
File name
•
INT
Primary display parameter being logged
•
EXT
Secondary display parameter being logged
•
INTVAL
Logging interval
•
D#
Current date in YYMMDD format
•
T#
Current time in HHMMSS format
NOTE: The chart and datalogging are independent functions; therefore the
parameter displayed on the chart may not necessarily reflect what is being
logged.
3.4.11 CALIBRATION
!
WARNING: These procedures require the use of specialized
test equipment and calibration adjustments should only be
carried out by qualified personnel.
POINT
-100
-90
-80
-70
-60
REF
-100.0
-90.0
-80.0
-70.0
-60.0
MDM300
-100.0
-90.0
-80.0
-70.0
-60.0
CALIBRATION
Figure 26 CALIBRATION Page
Entry to the CALIBRATION Menu is protected by a passcode (4876). The passcode is
entered in a similar manner to that described in Section 3.3.1.
This page gives access to the internal sensor’s calibration look-up table and provides the
facility to select and change any single point, or number of points.
The values in both the REF (reference dew-point) and MDM300 I.S. (reading at the
corresponding REF level input) columns can be edited.
Section 6 details the use of the calibration routines.
Michell Instruments
31
MDM300 I.S. User’s Manual
OPERATION
3.5
Default Parameters
Parameter
Default Value
Associated Section
Reference
SETTINGS
PRIMARY DP AT
DP/TEMP UNIT
PRESS UNIT
GAS TYPE
MOL WEIGHT
CHART INTERVAL
ATMOS
°C
psig
AIR
N/A
5 sec
Section 3.4.1, Figure 15
LOGGING
FILE NAME
PARAMETER
LOG INTERVAL
START?
DEWP
5 sec
STOPPED
BLUETOOTH
ENABLE
NAME
Section 3.4.2, Figure 16
NO
MDM300 I.S.
Section 3.4.3, Figure 17
NONE
N/A
N/A
Section 3.4.4, Figure 19
EXTERNAL
EXTERNAL TYPE
EXTERNAL ZERO
EXTERNAL SPAN
CLOCK
Current UK time & date
Section 3.4.5, Figure 20
HMI
CONTRAST
BRIGHTNESS
KEYTONE
BL TIME-OUT
LANGUAGE
PRIMARY DISP
80%
40%
OFF
OFF
ENG
INTERN
Section 3.4.6, Figure 21
CALIBRATION & INFO
Default values not
applicable
Section 3.4.11 & Section 6
Table 10 MDM300 I.S. Default Parameters
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MDM300 I.S. User’s Manual
3.6
OPERATION
Guide to Measurement and Sampling
Operating the MDM300 I.S. is very straightforward, but sampling conditions can vary
greatly from one application to another. To get the best possible response speed, the
appropriate procedure should be followed.
!
!
HIGH PRESSURE! High pressure gases are potentially
hazardous. Energy stored in these gases can be released
suddenly and with extreme force. High pressure systems
should be assembled and operated only by people who have
been trained in proper safety practices.
POSSIBLE INJURY! The tubing, valves and other apparatus
attached to this instrument must be adequate for the
maximum pressure which will be applied, otherwise physical
injury to the operator or bystander is possible.
For the most basic measurement it is recommended to have a flow meter (0 to 1 l/min),
and at least one metering valve.
A number of sampling kits are available from Michell Instruments:
•
The Easi-fit sample kit is a low cost sampling system consisting
of 2 metering valves and a flow meter which is suitable for many
applications.
•
The MDM300 panel-mount sampling system offers a complete package
for conditioning of a sample, prior to measurement with an MDM300.
It is contained within an optional flight case which allows for easy
transport of everything required to make the measurements. The antistatic construction of the case makes it suitable for use in hazardous
areas.
Figure 27 Easi-Fit Sample Kit
MDM300 Panel-Mount Sampling System
Specialized kits are available for the measurement of atmospheric pressure samples,
compressed air, medical gas and SF6. Contact a Michell Instruments’ representative for
more information.
Michell Instruments
33
MDM300 I.S. User’s Manual
OPERATION
!
3.6.1
It is highly recommended that a filter is installed upstream of
the MDM300. Refer to the Sample Conditioning section of the
Sampling Hints found in Section 4.1.
Measuring at Atmospheric or System Pressure
Without a metering valve
The large and small orifice fittings can be used to restrict flow at pressures up to 10
barg (145 psig).
To measure at atmospheric pressure, fit the small orifice fitting to the inlet of the
instrument. Fit a large orifice fitting to the outlet of the instrument.
To measure at system pressure, fit the small orifice fitting to the outlet of the instrument.
Fit a large orifice fitting to the inlet of the instrument.
Figure 28 Large and Small Orifice Fitting
With one metering valve
Ensure that large orifice fittings are fitted to both the inlet and the outlet of the
instrument.
To measure at atmospheric pressure the metering valve used to control the sample flow
should be fitted to the inlet of the instrument.
To measure at system pressure the metering valve used to control the sample flow
should be fitted to the outlet of the instrument.
With two metering valves
Ensure that large orifice fittings are fitted to both the inlet and the outlet of the
instrument.
To measure at atmospheric pressure the metering valve on the instrument outlet should
be fully open. The metering valve on the inlet should be used to control the sample flow.
To measure at system pressure the metering valve on the instrument inlet should be
fully open. The metering valve on the outlet should be used to control the sample flow.
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MDM300 I.S. User’s Manual
3.6.2
OPERATION
Measurement Guide
1.
Follow procedure A and note the result.
2.
Turn the instrument off.
3.
If you wish to measure at sample pressure then use the Michell Humidity
Calculator (http://www.michell.com/uk/downloads/humidity_calculator.
msi) to convert this result back to the equivalent at your sample pressure.
4.
Using this converted result, and the table below, find the appropriate
procedure to measure your sample.
Dew Point
>-40°C
<-40°C
Measure at
Sample Pressure
> 2.5 barg
Procedure B
Procedure C
Measure at
Atmospheric Pressure
Procedure A
Procedure A
Table 11 MDM300 I.S. Measurement Procedures
A
Standard Purge (Atmospheric Measurement)
1.
Connect the MDM300 I.S. to the sample gas stream.
2.
Adjust the flow rate, using the inlet flow control valve, to between 0.2
& 0.5 Nl/min (0.5 & 1 scfh). The outlet flow control valve should be fully
open.
3.
Turn the instrument on - the initialization period begins automatically.
The page will show a countdown of the remaining initialization time. The
status display will read ‘Initializing internal sensor’.
4.
After Initialization, the instrument will begin Measurement mode. During
the first few minutes of Measurement mode, the displayed moisture value
will drop rapidly below the actual moisture value, before returning to a
stable reading. The instrument display will show an initial measured
value, and the status display will show ‘Measurement in progress’.
5.
Once ‘Measurement in progress’ has disappeared, the instrument is
close to the final dew point. Depending on the conditions, it may continue
to respond for a number of minutes before tracking the measured dew
point.
Michell Instruments
35
OPERATION
36
MDM300 I.S. User’s Manual
B
Standard Purge (Pressure Measurement)
1.
Connect the MDM300 I.S. to the sample gas stream.
2.
Adjust the flow rate, using the outlet flow control valve, to between
0.2 & 0.5 Nl/min (0.5 & 1 scfh). The inlet flow control valve should be
fully open.
3.
Turn the instrument on - the initialization period begins automatically.
The page will show a countdown of the remaining initialization time. The
status display will read ‘Initializing internal sensor’.
4.
After Initialization, the instrument will begin Measurement mode. During
the first few minutes of Measurement mode, the displayed moisture value
will drop rapidly below the actual moisture value, before returning to
a stable reading. The instrument display will show an initial measured
value, and the status display will show ‘Measurement in progress’.
5.
Once ‘Measurement in progress’ has disappeared, the instrument is
close to the final dew point. Depending on the conditions, it may continue
to respond for a number of minutes before tracking the measured dew
point.
C
Enhanced Purge
1.
Connect the MDM300 I.S. to the sample gas stream.
2.
Adjust the flow rate, using the inlet flow control valve, to between 0.2
& 0.5 Nl/min (0.5 & 1 scfh). The outlet flow control valve should be fully
open.
3.
Turn the instrument on - the initialization period begins automatically.
The page will show a countdown of the remaining initialization time. The
status display will read ‘Initializing internal sensor’.
4.
Once 2-3 minutes of the initialization period have elapsed, close the outlet
flow control valve and fully open the inlet flow control valve. Then adjust
the flow rate using the outlet flow control valve to between 0.2 & 0.5 Nl/
min (0.5 & 1 scfh).
5.
After Initialization, the instrument will begin Measurement mode. During
the first few minutes of Measurement mode, the displayed moisture value
will drop rapidly below the actual moisture value, before returning to a
stable reading. The instrument display will show an initial measured
value, and the status display will show ‘Measurement in progress’.
6.
Once ‘Measurement in progress’ has disappeared, the instrument is
close to the final dew point. Depending on the conditions, it may continue
to respond for a number of minutes before tracking the measured dew
point.
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
3.6.3
OPERATION
Conditional Sensor Purge
In order to ensure consistently fast measurement response speeds after power Off/On,
the sensor will not be automatically purged when the measured dew point is deemed to
be sufficiently close to the previously measured dew point.
3.7
Battery Management
The battery will typically provide 24 hours of continuous operation from full charge.
When the battery approaches discharge, the instrument will display the warning
message ‘Battery low – recharge now’.
Following this, the instrument will enter a Shutdown Mode, accompanied by an audible
beep. This mode will disable the operation of the keypad and display backlight, preventing
further usage of the unit. Upon connecting the instrument to the battery charger it will
exit Shutdown Mode within 30 seconds.
When Shutdown Mode occurs, connect the instrument to the battery charger as soon
as possible to prevent complete discharge. Complete discharge may occur if the unit is
not connected to a battery charger within a 24 hour period - see below.
!
3.7.1
WARNING: If complete discharge does occur, then
difficulties may be encountered when attempting to
recharge the battery.
If this problem is experienced, refer below for a possible
solution.
Battery Troubleshooting
Problem:
Instrument battery is flat and will not charge.
(NOTE: OLDER FW 7219 MODEL BATTERY CHARGER ONLY).
Cause:
If the instrument has been left in a completely discharged state for
several days then it is possible that the FW 7219 charger will not
recharge the battery.
Solution:
The instrument will need to be connected to a 6 V (500 mA max) power
supply – via its normal charging port – for a maximum of 15 seconds
before switching to the FW 7219 charger, which should now behave
normally.
!
DO NOT leave this 6 V power supply connected to the
instrument for any longer than the recommended 15 seconds
or the battery may be damaged.
NOTE: Michell Instruments will replace the older FW 7219 charger with the
new Cell Con model free of charge. The Cell Con will re-charge batteries which
have completely discharged.
Michell Instruments
37
MDM300 I.S. User’s Manual
GOOD MEASUREMENT PRACTICE
4
GOOD MEASUREMENT PRACTICE
The MDM300 I.S. is designed to operate in a flowing gas stream with flow rates between
0.2 and 0.5 Nl/min (0.5 and 1 scfh). Flow regulation is provided with the MDM300 I.S.
instrument between 2.5 and 10 barg. Outside of this, the sample flow must be regulated
outside the unit.
For all applications, the sample gas is taken into the instrument via the Gas In port
(2) Figure 5 located on the top of the instrument, from where it passes through the
internal sensor and out via the Gas Out port (1) Figure 5. Gas flow rate (if monitored)
is normally measured externally, on the output side of the instrument.
There are a number of options for sample conditioning including a purpose built sampling
system and a variety of application kits. The flow rate can be regulated on the inlet
or outlet depending on whether the intention is to measure at atmospheric or sample
pressure. Up to 10 barg, this can be achieved by use of the orifice fittings supplied with
the instrument. Section 2.5.1 and Figure 8 show a typical arrangement for measuring
non-hazardous gas at atmospheric or elevated pressure.
In applications where the sample gas has a very high flow rate it is advisable to use
an instrument by-pass arrangement to provide the minimal flow rates which the sensor
requires. Excessive flow restriction can cause back-pressure across the sensor, leading
to a discrepancy between the readings recorded and those expected.
Note: Dew-point is dramatically affected by changes in pressure - in order to
ensure the best performance from the instrument it is essential to adequately
regulate the sample pressure.
Ideally, a good quality pressure regulator should be used in conjunction with a fine
adjustment needle valve. Using a needle valve exclusively is acceptable, but only if the
sample pressure downstream of the nearest regulator is not susceptible to pressure
fluctuations greater than ±250 millibar.
Measurement of Dew Points Drier than -70°Cdp
The MDM300 I.S. Sampling System is optimized for fast response. Therefore, when
measuring very dry dew points, certain steps need to be taken to ensure that the best
accuracy is achieved:
Make sure that all tubing and fittings used are made from stainless steel.
This should reduce the possibility of any moisture being trapped upstream of the sensor
prolonging the dry-down process, or permeating into the sample line through unsuitable
tubing - such as PTFE.
Due to the significantly lower levels of moisture present at dew points of this level, the
response times of the sensor will be significantly increased. The table below offers an
approximate guide to the times taken for the instrument to stabilize at a given dew
point (from a starting point of 10°Cdp ambient):
Target Dew Point (°C)
-80
-90
-100
38
T100 response time from ambient (hours)
12
48
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4.1
GOOD MEASUREMENT PRACTICE
Sampling Hints
Measurement of moisture content is a complex subject, but does not need to be difficult.
This section aims to explain the common mistakes made in measurement situations, the
causes of the problem, and how to avoid them. Mistakes and bad practices can cause
the measurement to vary from the expectation; therefore a good sampling technique is
crucial for accurate and reliable results.
Transpiration and Sampling Materials
- 20
Dew point (ºC)
- 30
nylon
- 40
- 50
copper
- 60
polyethylene
- 70
nickel
stainless steel
1
2
3
Time (hours)
4
PTFE
5
All materials are permeable to water vapor, as the water molecule is extremely small
compared to the structure of solids, even when compared to the crystalline structure of
metals. The graph to the right shows the dew point inside tubing of different materials
when purged with very dry gas, where the exterior of the tubing is in the ambient
environment.
Many materials contain moisture as part of their structure, particularly organic materials
(natural or synthetic), salts (or anything which contains them) and anything which
has small pores. It is important to ensure that the materials used are suitable for the
application.
If the partial water vapor pressure exerted on the outside of a compressed air line is
higher than on the inside, the atmospheric water vapor will naturally push through the
porous medium causing water to migrate into the pressurized air line. This effect is
called transpiration.
Adsorption and Desorption
Adsorption is the adhesion of atoms, ions, or molecules from a gas, liquid, or dissolved
solid to the surface of a material, creating a film. The rate of adsorption is increased at
higher pressures and lower temperatures.
Desorption is the release of a substance from or through the surface of a material. In
constant environmental conditions, an adsorbed substance will remain on a surface
almost indefinitely. However, as the temperature rises, so does the likelihood of
desorption occurring.
In practical terms, as the temperature of the environment fluctuates, water molecules
are adsorbed and desorbed from the internal surfaces of the sample tubing, causing
small fluctuations in the measured dew point.
Michell Instruments
39
GOOD MEASUREMENT PRACTICE
MDM300 I.S. User’s Manual
Sample Tubing Length
The sample point should always be as close to the critical measurement point as possible,
in order to obtain a truly representative measurement. The length of the sample line
to the sensor or instrument should be as short as possible. Interconnection points and
valves trap moisture, so using the simplest sampling arrangement possible will reduce
the time it takes for the sample system to dry out when purged with dry gas.
Over a long tubing run, water will inevitably migrate into any line, and the effects of
adsorption and desorption will become more apparent. It is clear from the graph shown
above that the best materials to resist transpiration are stainless steel and PTFE.
Trapped Moisture
Dead volumes (areas which are not in a direct flow path) in sample lines, hold onto
water molecules which are slowly released into the passing gas; this results in increased
purge and response times, and wetter than expected readings. Hygroscopic materials
in filters, valves (e.g. rubber from pressure regulators) or any other parts of the system
can also trap moisture.
Sample Conditioning
Sample conditioning is often necessary to avoid exposure of sensitive measuring
components to liquids and other contaminants which may cause damage or affect the
accuracy over time, depending on the measurement technology.
Particulate filters are used for removing dirt, rust, scale and any other solids that may
be in a sample stream. For protection against liquids, a coalescing filter should be used.
The membrane filter is a more expensive but highly effective alternative to a coalescing
filter. It provides protection from liquid droplets, and can even stop flow to the analyzer
completely when a large slug of liquid is encountered.
Condensation and Leaks
Dewpoint > T
Dewpoint < T
Maintaining the temperature of the sample system tubing above the dew point of the
sample is vital to prevent condensation. Any condensation invalidates the sampling
process as it changes the water vapor content of the gas being measured. Condensed
liquid can alter the humidity elsewhere by dripping or running to other locations where
it may re-evaporate.
The integrity of all connections is also an important consideration, especially when
sampling low dew points at an elevated pressure. If a small leak occurs in a high
pressure line, gas will leak out but vortices at the leak point and a negative vapor
pressure differential will also allow water vapor to contaminate the flow.
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GOOD MEASUREMENT PRACTICE
Flow Rates
Theoretically flow rate has no direct effect on the measured moisture content, but in
practice it can have unanticipated effects on response speed and accuracy. The optimal
flow rate varies depending on the measurement technology, and can always be found
in the instrument or sensor manual.
An inadequate flow rate can:
•
Accentuate adsorption and desorption effects on the gas passing
through the sampling system.
•
Allow pockets of wet gas to remain undisturbed in a complex sampling
system, which will then gradually be released into the sample flow.
•
Increase the chance of contamination from back diffusion: ambient air
that is wetter than the sample can flow from the exhaust back into the
system. A longer exhaust (sometimes called a pigtail) can also help
alleviate this problem.
•
Slow the response of the sensor to changes in moisture content.
An excessively high flow rate can:
•
Introduce back pressure, causing slower response times and
unpredictable effects on equipment such as humidity generators.
•
Result in a reduction in heating capabilities of the sensor tile during
the initialization period. This is most apparent with gases that have a
high thermal conductivity such as hydrogen and helium.
!
POSSIBLE INJURY! The tubing, valves and other apparatus
attached to this instrument must be adequate for the
maximum pressure which will be applied, otherwise physical
injury to the operator or bystander is possible.
!
Before disconnecting the MDM300 I.S. from the gas line
it is essential to vent the system to atmospheric pressure,
otherwise severe injury could result.
Michell Instruments
41
APPLICATION SOFTWARE
5
MDM300 I.S. User’s Manual
APPLICATION SOFTWARE
Application software for the MDM300 I.S. is supplied on a CD.
The latest version of this application software is also available for download from the
Michell website – http://www.michell.com/uk/support/sware-downloads.htm.
To install on a PC: place the CD in the CD drive and follow the instructions in the
application set-up wizard. If the CD does not auto-run, double-click the application
set-up file on the CD. The following authorization code will be required during the
installation process: MDM-300-7392
Once the software has been installed and run, the MDM300 I.S. can be linked to the PC
by activating the Bluetooth on the MDM300 I.S. and then connecting with the application
software (see Section 3.4.3 for details).
The application software allows modification of all the instrument parameters from the
connected PC. The settings currently stored on the MDM300 I.S. can be downloaded to
the PC by clicking the ‘Download from MDM300’ button, and can then be changed and
stored by clicking the ‘Upload to MDM300’ button.
The software gives access to all logging files stored on the instrument’s internal
memory. These can be downloaded to a specific location by right clicking, and selecting
‘download’.
A context sensitive help file provides further details on the use of the application
software.
Figure 29 Typical Application Software Screen
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MDM300 I.S. User’s Manual
6
CALIBRATION
6.1
Traceability
CALIBRATION
The calibration of this instrument is traceable to national standards. For this reason
the instrument should only be calibrated in an accredited, e.g. UKAS or NIST (U.S.)
standards laboratory.
If these facilities do not exist it is recommended that the instrument be returned to the
manufacturer, Michell Instruments Ltd., or one of the approved agents.
A calibration certificate bearing a seven point calibration is issued with each instrument.
Figure 30 shows a typical seven point calibration certificate.
Figure 30 Typical 7-point Calibration Certificate
Michell Instruments
43
MDM300 I.S. User’s Manual
CALIBRATION
6.2
Calibration Method
!
WARNING:
These procedures require the use of specialized test
equipment and calibration adjustments should only be carried
out by qualified personnel. If not correctly carried out, the
instrument’s calibration can be lost.
The calibration procedure for the instrument is as follows:
1.
Switch on the instrument. Wait for the initialization period to complete
and allow sufficient time for it to stabilize.
2.
Ensure the instrument is set up with sample gas as AIR and operating pressure
as ATMOS.
3.
Ensure that the temperature units are set up as °C and the primary display is
reading Dew point.
4.
Ensure that all sample tubing and connectors are made from stainless steel and
are of suitable quality.
5.
Connect the MDM300 I.S. to a dew-point generator and establish a gas flow
through the instrument.
6.
Apply a dew point of -100°C and allow the instrument’s reading to stabilize for a
minimum of 96 hours (including dry down).
7.
Record the applied REF dew point and the corresponding MDM300 I.S. display
reading.
8.
Repeat steps 6 and 7 at all the required dew-point values over the operating
range of the instrument, as shown in Table 12, allowing the stabilization times
shown before recording consecutive readings.
A set of results similar to that shown below could be generated over the calibration range of
the instrument.
DP REF
°C
-100
-80
-70
-60
-50
-40
Stabilize
Time
(Hours)
96
12
8
4
2
1
MDM300 I.S.
Rdg °C
DP REF
°C
-99.8
-79.7
-70
-59.8
-49.8
-39.9
-30
-20
-10
0
10
20
Stabilize
Time
(Hours)
1
1
1
1
1
1
MDM300 I.S.
Rdg °C
-30.1
-19.9
-10
0.1
10
20
Table 12 Example Of Calibration Run Readings
44
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MDM300 I.S. User’s Manual
6.3
CALIBRATION
Calibration Correction Method
NOTE: Any logging procedure currently in operation must be cancelled before
the calibration procedures can be entered.
To enter the CALIBRATION Menu page, highlight CALIBRATION from the SET-UP Menu
by using the  or  keys and press the Enter key.
Entry to the CALIBRATION Menu is protected by a passcode (4876).
Once the passcode has been successfully entered, the following page will be shown.
POINT
-100
-90
-80
-70
-60
REF
-100.0
-90.0
-80.0
-70.0
-60.0
MDM300
-100.0
-90.0
-80.0
-70.0
-60.0
CALIBRATION
Figure 31 Calibration Menu Page
The MDM300 I.S. Calibration look-up table is divided into three columns.
The values in the first column POINT represent the thirteen nominal calibration points,
spread at 10°C intervals over the instruments operating range of -100 to +20°C (-148
to +68°F). These points cannot be edited.
The second column REF represents the value of the reference dew-point standard
applied at that particular point.
The third column MDM300 represents the reading that the MDM300 I.S. was showing
at the corresponding REF level input.
The values in both the REF and MDM300 I.S. columns can be edited by means of the
 and  keys. The  and  keys provide the means of switching between corresponding
table columns.
After changes have been made press the Enter key to reach the Exit page. No changes
are implemented until the  key is pressed at the Exit page.
To exit without implementing any changes, press the Enter key to reach the Exit page.
Press the  key, from the Exit page, to return to the SET-UP Menu.
Michell Instruments
45
MDM300 I.S. User’s Manual
SHIPPING
7
SHIPPING
For shipping purposes the instrument should be packed into its original carton which
will provide the recommended degree of protection during transit.
To prepare the instrument for shipping, proceed as follows:
1.
Switch the instrument off and remove any connections to the Gas In and
Gas Out ports and any external sensors connected to it.
2.
If fitted, remove the instrument from its carrying case.
3.
Pack the instrument in its original carton (1) as shown below.
NOTE: It is not necessary to return any accessories unless they
require repair/replacement. Any returned accessories can be
packed in the box (4).
4.
Before disconnecting the MDM300 I.S. from the gas line it is essential to
vent the system to atmospheric pressure, otherwise severe injury could
result.
- I.S.
va
nc
ed M
D DM
U ew 30
se -P 0
r’s o I.
M int S.
an H
ua yg
l rom
et
er
!
Create a packing list detailing all equipment contained in the box, place it
inside the box and seal the box.
ct
o
b
er
08
Se
97
21
pt 3
em Is
be su
r 20e
4
12
Ad
4
00
00
0
Is
su
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1
00
00
0
O
Is
su
ct
ob
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er
1
08
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3
-
I.S
.
2
1
Figure 34 Instrument Packing Details
46
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
APPENDIX A
Appendix A
Technical Specifications
Michell Instruments
47
MDM300 I.S. User’s Manual
APPENDIX A
Appendix A
Technical Specifications
Performance
Measurement Technology
Michell Ceramic Sensor
Accuracy
±1°C from -60 to +20°Cdp (-76 to +68°Fdp)
±2°C from -100 to -60°Cdp (-148 to -76°Fdp)
±0.2°C (0.3°F) temperature
Calibrated Measurement Range
For Spot Checks
For Online Analysis
Uncalibrated Readings From
+20 to +30°Cdp (+68 to +86°Fdp)
Measurement Units
°C, °F, K dew point & gas temperature
% RH, ppmV, g/m3
ppmW & g/kg (for air, N2, H2, CO2, SF6, user-defined mw)
ppmV, lb/mmscf & g/m3 for natural gas
Pressure Units
psig, barg, KPa, bara, psia, MPa
Resolution (display)
0.1 for all dew-point derived units & auto ranging where appropriate
Resolution (measurement)
Better than 0.1°Cdp (0.2°Fdp)
Typical Response Speed
T95 in ≤30 minutes to -60°Cdp (-76°Fdp)
Sample Gas Flow
0.2 to 0.5 Nl/min (0.5 to 1 scfh)
-70 to +20°Cdp (-95 to +68°Fdp)
-100 to -70°Cdp (-148 to -95°Fdp)
Electrical Specifications
Auxiliary Inputs
Connection to Michell Easidew I.S. or Easidew PRO I.S. via Remote
Sensor Interface
Battery
4.8 V internally mounted Nickel Metal Hydride (NiMH) battery
Battery Operating Life
Up to 24 hours of typical usage between charges
Battery Charger
Intelligent charger, NOT certified for hazardous area use
Charger supply voltage: 100 to 240 V AC, 50/60 Hz, 8 VA
Operating Conditions
Operating Pressure
0 to 35 MPa (0 to 350 barg / 0 to 5076 psig)
Operating Environment
Outdoors 0 to +100% RH (non-condensing)
Operating Temperature
-20 to +50°C (-4 to +122°F)
Storage / Transport Temperature
-40 to +70°C (-40 to +158°F)
Altitude
Up to 2000m (6562ft)
Mechanical Specifications
Display
Blue LCD graphical display
Enclosure Type
Steel fiber-loaded high-impact polyamide 6
IP/NEMA Rating
IP66/NEMA 4
Gas Connections
1/8” NPT female (other options available)
Gas Wetted Materials
AISI 316L stainless steel, PTFE Seal, Borosilicate glass, ceramic
Outline Dimensions
218 x 170 x 90mm (8.6 x 6.7 x 3.5ft) (d x w x h)
Weight
1.5kg (3.3lbs)
48
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
APPENDIX A
Data Logging
Capacity: 8Mb
Log interval: 5 to 60 sec
Maximum log file size: 60kb
Communications
(Wireless) BluetoothTM range up to 5m (16ft) (Version 2.0)
Languages
English, German, Spanish, French, Italian, Portuguese
Hazardous Area Certification
Certification Codes
Dimensions
170mm (6.69”)
218mm (8.56”)
A.1
ATEX II 1G Ex ia IIC T4 Ga (-20°C to +50°C)
IECEx
Ex ia IIC T4 Ga (-20°C to +50°C)
INMETRO
Ex ia IIC T4 Ga (-20°C to +50°C)
TC TR Ex
0Ex ia IIC T4 Ga
FM
Class I, Division 1, Groups A B C D, T4
CSA
Class I, Division 1, Groups A B C D, T4
90mm (3.54”)
Figure 35 Dimensions - MDM300 I.S.
Michell Instruments
49
APPENDIX B
MDM300 I.S. User’s Manual
Appendix B
Datalog Status Display
50
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
Appendix B
APPENDIX B
Datalog Status Display
When the status of the current log file is displayed, see Figure 33, the ST column in
the current log file display represents the instrument’s status at the time that each log
point is recorded.
#
106
107
108
109
110
INT EXT
26.8 -100.0
26.2
-90.0
-80.0
25.9
-70.0
25.8
25.5
-60.0
ST
0028
0028
0028
0028
0028
File
INT
EXT.
INTVAL
D#
T#
CR270309
RH
EXT_DP
05 Sec
090327
123606
Figure 36 Current Datalog File Display
This column shows a hexadecimal representation of the instrument’s 16-bit status
register shown below in Figure 36. Bit 1 is the least significant bit. The four most
significant bits 13 to 16 are for Michell Instruments’ service use and so the first character
in any MDM300 I.S. ST display will always read 0.
Status register bit position
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
N/A N/A N/A N/A
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
N/A
Figure 37 MDM300 I.S. Status Register
For the example given for each of the log plots shown in Figure 35 (Hex 0028), the
output pattern of the status register will be as shown in Figure 37.
16 15 14 13
N/A N/A N/A N/A
12
0
Status register bit position
11 10
9
8
7
6
0
0
0
0
0
1
5
0
4
1
3
0
2
0
1
N/A
Figure 38 MDM300 I.S. Status Register (Hex 28)
Each of the error bits set high (1) represents a specific status or error condition. In this
example, bits 4 and 6 are set high indicating that two (status) conditions exist.
Michell Instruments
51
MDM300 I.S. User’s Manual
APPENDIX B
Table 13 shows the status flags associated with each bit of the status register. If a
status flag is set high then the associated condition exists. If it is set low, then that
condition does not exist.
Status Register
Message
bit in Hex
Details
Dew-point reading out of range (> +30 / <
-120°C)
0x0002 = BIT 2
Internal sensor
error
0x0004 = BIT 3
Internal thermistor range (> +100 / < -40°C) or
error
0x0008 = BIT 4
External sensor
error
Battery low
Measurement in
progress
0x0010 = BIT 5
0x0020 = BIT 6
Sensor internal temperature reading out of
Thermistor fault
0x0040 = BIT 7
0x0080 = BIT 8
Log finished
Internal sensor not
found
Default CONFIG file
0x0200 = BIT 10
used
Initializing Internal
0x0800 = BIT 12
Sensor
0x0100 = BIT 9
External Sensor Input out of range (< 4 mA /
> 20 mA)
Battery level low - recharge as soon as possible
Internal dew point not stable
Internal dew point changing <0.2°Cdp over a 3
minute interval
Log file has reached the maximum of 10,000
logs and logging has been stopped
Could not detect internal sensor on power up
Config. file missing, new file created and default
settings used
Indicates system in purging phase
Table 13 Status Register Flags
For the example given in Figure 35, from Table 13, Hex 28 translates, reading from right
to left, as bit 4 set ‘External sensor error’ and bit 6 set ‘Measurement in progress’.
Therefore, at the time that these log points were taken, the external sensor was out of
range and the internal dew point was not stable.
52
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
APPENDIX C
Appendix C
Hazardous Area
Certification
Michell Instruments
53
MDM300 I.S. User’s Manual
APPENDIX C
Appendix C
Hazardous Area Certification
The MDM300 I.S is certified compliant to the ATEX Directive (2014/34/EU) and IECEx for
use within Zone 0 Hazardous Area, and has been assessed so by Baseefa Ltd (Notified
Body 1180).
The MDM300 I.S is certified compliant to North American Standards (USA and Canada)
for use within Class I, Division 1, Groups A, B, C & D Hazardous Locations and has been
assessed so by CSA and FM.
C.1
Product Standards
This product conforms to the Standards:
EN60079-0:2009
EN60079-26:2007
EN60079-11:2007
CAN/CSA-C22.2 No.0-M10
CAN/CSA-C22.2 No. 157-92(R2012)
CAN/CSA-C22.2 No.142-M1987(R2009)
ANSI/IEC 60529:2004
C.2
IEC60079-11:2006
IEC60079-0:2007-10
IEC60079-26:2006
FM CLASS 3600:1998
FM CLASS 3610:2010
FM CLASS 3810:2005
Product Certification
This product is attributed with the product certification codes:
ATEX & IECEx
II 1 G Ex ia IIC T4 Ga (-20°C to +50°C)
North American
IS - Class I, Division 1, Groups A, B, C, D, T4
C.3
Global Certificates/Approvals
ATEX
IECEx
FM
CSA
TC TR Ex
INMETRO
BASEEFA09ATEX0149
IECEX BAS09.0063
3036712
2318983
RU C-GB. ГБ05.B.00229
NCC14.03165
These certificates can be viewed or downloaded from our website at:
http://www.michell.com
C.4
Input Terminal Parameters
External Sensor Socket
54
Ui
= 28 V
Ii
= 93 mA
Pi
= 650 mW
PO
=0
Ci
=0
Li
=0
Charging Socket
Um
= 18V
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
C.5
APPENDIX C
Special Conditions of Use
None
C.6
Maintenance and Installation
The MDM300 I.S. must only be installed by suitably qualified personnel and in accordance
with the instructions provided and the terms of the applicable product certificates.
Maintenance and servicing of the product must only be carried out by suitably trained
personnel or returned to an approved Michell Instruments’ Service Center.
Michell Instruments
55
APPENDIX D
MDM300 I.S. User’s Manual
Appendix D
FCC Declaration
56
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
Appendix D
APPENDIX D
FCC Declaration
MDM300 I.S. Advanced Dewpoint Hygrometer.
This Device complies with FCC Rules Part 15 Subpart B Unintentional Radiators
Class B digital devices. Operation is subject to the following conditions:
1) This device may not cause harmful interference
2) This device must accept any interference received, including interference that may cause
undesired operation.
Note: This product has been tested and found to comply with the limits or Class B digital devices,
pursuant to Part 15 of the FCC rules. This product generates, uses and can radiate radio frequency
energy and, if not installed and used in accordance with the instructions, may cause harmful
interference to radio communications. However, there is no guarantee that interference will not in a
particular installation. If this product does cause harmful interference to radio reception, which may be
determined by turning the product on & off, the user is encouraged to try to correct the interference by
one or more of the following measures:
Reorient or relocate the receiving antenna,
Increase the separation between the product and receiver,
Connect the equipment into an outlet on a circuit different from that to which the receiver is
connected
Consult the dealer or an experienced radio/TV technician for help.
This product must be operated as per the operating instructions provided.
Do not make any alterations or modifications to the product. Any unauthorised alterations or
modifications made to this product may require you to stop operating the product.
Canadian Radio Interference Regulations.
This Class B digital product complies with Canadian ICES-003, CISPR 22 :1997.
Règlement canadien sur les interférences radio.
Ce produit numérique de classe B est conforme à la norme NMB-003, CISPR 22: 1997.
Signed for, and on behalf of,
Michell Instruments Ltd.
Andrew M.V. Stokes, Technical Director
Issue date: 05/2011
Michell Instruments
57
APPENDIX E
MDM300 I.S. User’s Manual
Appendix E
Quality, Recycling
& Warranty
Information
58
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
Appendix E
APPENDIX E
Quality, Recycling & Warranty Information
Michell Instruments is dedicated to complying to all relevant legislation and directives. Full information
can be found on our website at:
www.michell.com/compliance
This page contains information on the following directives:
•
ATEX Directive
•
Calibration Facilities
•
Conflict Minerals
•
FCC Statement
•
Manufacturing Quality
•
Modern Slavery Statement
•
Pressure Equipment Directive
•
REACH
•
RoHS2
•
WEEE2
•
Recycling Policy
•
Warranty and Returns
This information is also available in PDF format.
Michell Instruments
59
APPENDIX F
MDM300 I.S. User’s Manual
Appendix F
Return Document &
Decontamination Declaration
60
97213 Issue 5, October 2017
MDM300 I.S. User’s Manual
Appendix F
APPENDIX F
Return Document & Decontamination Declaration
'HFRQWDPLQDWLRQ&HUWL¿FDWH
IMPORTANT NOTE: Please complete this form prior to this instrument, or any components, leaving your
site and being returned to us, or, where applicable, prior to any work being carried out by a Michell
engineer at your site.
Instrument
Warranty Repair?
Serial Number
YES
NO
Company Name
Original PO #
Contact Name
Address
Telephone #
E-mail address
Reason for Return /Description of Fault:
Has this equipment been exposed (internally or externally) to any of the following?
Please circle (YES/NO) as applicable and provide details below
Biohazards
YES
NO
Biological agents
YES
NO
Hazardous chemicals
YES
NO
Radioactive substances
YES
NO
Other hazards
YES
NO
Please provide details of any hazardous materials used with this equipment as indicated above (use continuation sheet
if necessary)
Your method of cleaning/decontamination
Has the equipment been cleaned and decontaminated?
YES
NOT NECESSARY
Michell Instruments will not accept instruments that have been exposed to toxins, radio-activity or bio-hazardous
PDWHULDOV)RUPRVWDSSOLFDWLRQVLQYROYLQJVROYHQWVDFLGLFEDVLFÀDPPDEOHRUWR[LFJDVHVDVLPSOHSXUJHZLWKGU
JDV GHZSRLQWƒ& RYHUKRXUVVKRXOGEHVXI¿FLHQWWRGHFRQWDPLQDWHWKHXQLWSULRUWRUHWXUQ
Work will not be carried out on any unit that does not have a completed decontamination declaration.
Decontamination Declaration
I declare that the information above is true and complete to the best of my knowledge, and it is safe for Michell
personnel to service or repair the returned instrument.
Name (Print)
Position
Signature
Date
F0121, Issue 2, December 2011
Michell Instruments
61
MDM300 I.S. User’s Manual
NOTES:
62
97213 Issue 5, October 2017
http://www.michell.com

Please fill out the form(s) below for each instrument that has been purchased.

Use this information when contacting Michell Instruments for service purposes.

Hygrometer

Code

Serial Number

Invoice Date

Location of Instrument

Tag No

Hygrometer

Code

Serial Number

Invoice Date

Location of Instrument

Tag No

Hygrometer

Code

Serial Number

Invoice Date

Location of Instrument

Tag No

This document is the property of Michell Instruments Ltd. and may not be copied or otherwise reproduced, communicated in any way to third parties, nor stored in any Data Processing System without the express written authorization of Michell Instruments Ltd.

1 INTRODUCTION

The MDM300 I.S. Advanced Dew-Point Hygrometer is a portable instrument designed for online measurement of moisture content in non-corrosive gases in hazardous areas, over an operational range of -100 to +20°C (-148 to +68°F).

The instrument is independently assessed and certificated as being intrinsically safe and fully compatible with safe operation within defined Zone 0 hazardous areas.

The instrument is contained within a steel fiber-loaded high-impact polyamide 6 case, sealed to IP66 / NEMA4 standard and is powered by an internally mounted Nickel Metal Hydride (NiMH) battery, designed to typically provide 24 hours continuous use between charges. Continuous battery charge status indication is provided. Additional battery status information is provided by a battery indicator icon, in addition to a warning beep and Shutdown Mode.

The MDM300 I.S. is fitted with an internally mounted ceramic sensor, which is enhanced for a quicker response to dew points as dry as -75°Cdp (-103°Fdp).

The MDM300 I.S. can also be used to read the dew-point signal from a Michell Instruments’ Easidew I.S. transmitter. To do this, the MDM300 I.S. Remote Sensor Interface is used to connect to the Easidew I.S. transmitter.

No other sensor can be connected to the MDM300 I.S.

A graphical display presents the dew-point data in large format characters and simultaneously provides a primary display of real time dew-point readings and a secondary display, in smaller characters, for the external sensor input. If no external input is programmed, gas temperature (measured by the internal sensor) is displayed by default.

A fully programmable, real-time, datalogging facility is provided which has an internal memory capacity of 8Mb, capable of storing up to 10,000 logs per file (typically giving a maximum of 64 log files).

A Bluetooth, wireless, communication system is provided, giving access to a dedicated, PC based, MDM300 I.S. Software Application Package which provides the facility for handling the logged data files and uploading and downloading instrument parameters.

A user-friendly operator interface provides easy access to all levels of the instrument’s functionality.

An easy-to-follow calibration routine is built into the instrument’s software.

1.3.1Display Units

The instrument can display the measured reading in the following units:

Absolute Humidity

•lb/MMscf

•g/m3

•g/m3 NG

Moisture Content

•ppmV NG

•ppmV

•ppmW (AIR, USER, H2, SF6, CO2 or N2)

Dew Point

•°C

•°F

•K

Relative Humidity (%)

Mixing Ratio

•g/kg (AIR, USER, H2, SF6, CO2 or N2)

To toggle between displayed units, press either the  or  key.