Michell Instruments MDM50 Operating Manual

MDM50

Standard Version

User’s Manual

97475 Issue 1.3

March 2016

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Use this information when contacting Michell Instruments for service purposes.

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Instrument

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MDM50

For Michell Instruments' contact information please go to

www.michell.com

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.

MDM50 LP Version User’s Manual

Contents

Safety ................................................................................................................................ v

Electrical Safety ........................................................................................................... v

Pressure Safety ............................................................................................................ v

Toxic Materials ............................................................................................................. v

Repair and Maintenance ............................................................................................... v

Calibration ................................................................................................................... v

Safety Conformity ........................................................................................................ v

Abbreviations ......................................................................................................................vi

Warnings ............................................................................................................................vi

1 INTRODUCTION ................................................................................................1

2 INSTALLATION ..................................................................................................2

3 OPERATION ......................................................................................................3

3.1 General Operation .............................................................................................. 3

3.2 Atmospheric or Line Pressure Measurements ........................................................ 4

3.3 Measuring Dew Points Below -40°C (-40°F) .......................................................... 5

3.4 User Controls ..................................................................................................... 6

3.5 4-20 mA Output Socket Wiring ............................................................................ 7

4 GOOD MEASUREMENT PRACTICE .......................................................................8

5 MAINTENANCE ................................................................................................12

5.1 Calibration ....................................................................................................... 12

5.2 Transmitter / Battery Replacement ..................................................................... 12

5.3 Filter Cartridge Replacement ............................................................................. 14

5.4 Checking the MDM50 Electronics Calibration ....................................................... 14

5.5 List of Spares ................................................................................................... 14

5.6 Troubleshooting ................................................................................................ 15

Figures

Figure 1 Interchangeable Gas Inlet/Outlet Fittings .....................................................4

Figure 2 User Controls .............................................................................................6

Figure 3 Jack Plug Wiring .........................................................................................7

Figure 4 2-Wire Connection - View Showing Rear of Connector Terminal Block ...........14

Appendices

Appendix A Technical Speciﬁ cations .............................................................................. 17

Appendix B EU Declaration of Conformity......................................................................19

Appendix C Quality, Recycling & Warranty Information ...................................................21

C.1 Pressure Equipment Directive (PED) 97/23/EC ............................... 21

C.2 Recycling Policy ..........................................................................21

C.3 WEEE Compliance ........................................................................ 21

C.4 RoHS2 Compliance ......................................................................22

C.5 Warranty ..................................................................................... 22

C.6 REACH Compliance ...................................................................... 23

C.7 Return Policy ............................................................................... 23

C.8 Calibration Facilities .....................................................................24

C.9 Manufacturing Quality .................................................................. 24

C.10 FCC (EMC Requirements for North America) ..................................24

Appendix D Decontamination Declaration ...................................................................... 26

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MDM50 LP Version 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 qualiﬁ ed personnel and 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. The input power supply voltage limits for the battery charger supplied with the instrument are 90 to 264 V AC, 47/63 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 speciﬁ ed safe working pressure is 20 barg (290 psig). Refer to the Technical Speciﬁ cations in Appendix A.

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 ofﬁ ces contact information.

Calibration

The recommended calibration interval for the MDM50 is one year, unless otherwise speciﬁ ed by Michell Instruments Ltd. The instrument should be returned to the manufacturer, Michell Instruments, or one of their accredited service agents for re-calibration (go to www.michell.com for contact information).

Safety Conformity

This product meets the essential protection requirements of the relevant EU directives. Further details of applied standards may be found in the product speciﬁ cation.

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Abbreviations

The following abbreviations are used in this manual:

AC alternating current

atm pressure unit (atmosphere)

barg pressure unit (=100 kP or 0.987 atm) gauge

°C degrees Celsius

°F degrees Fahrenheit

dp dew point

ft feet

kg kilogram

lb pound

MDM50 LP Version User’s Manual

mA milliampere

m meter

mm millimeter

MPa megapascal

Nl/min normal liters per minute

psig pound(s) per square inch (gauge)

scfh standard cubic feet per hour

μm micrometer

Ω ohm

V Volts

Warnings

The following general warnings listed below are applicable to this instrument. They are 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.

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MDM50 LP Version User’s Manual

1 INTRODUCTION

The MDM50 comprises a fast responding polymer sensor ﬁ tted into a sample block with an integrated ﬁ lter cartridge, and Legris push ﬁ ttings or optional Swagelok® tube ﬁ ttings on the gas inlet and outlet. The measured dew point from the sensor is shown on the clear red LED display on the front panel of the instrument.

The MDM50 can be supplied with either °C or °F dew-point measurement units.

A 4-20 mA analog output is provided for connection to a chart recorder, data-logger or computer system, so dew-point trends can be analyzed over time.

The electronics are housed in a rugged Peli case, providing NEMA 6 protection when the lid is closed. The case is supplied with a lifetime guarantee.

INTRODUCTION

The MDM50 is powered by a rechargeable NiMH battery pack, giving between 12 and 16 hours of measurement time from a full charge. The instrument is delivered complete with a universal battery charger stored in the lid. It takes 16 hours to fully charge the battery pack, during which time the instrument can be switched on or off. The charger is suitable to connect power to the instrument indeﬁ nitely, but it is recommended to allow the battery pack to go through a full charge-discharge cycle at least once per month. A battery charge indicator on the instrument front panel warns when the battery is low.

MDM50 polymer moisture sensors are subject to a 9-point calibration, where their performance is characterized against a fundamental reference hygrometer. This process, and subsequent quality testing, ensures that all sensors behave optimally before they are used in the ﬁ eld. Each MDM50 is supplied with a calibration certiﬁ cate traceable to national standards (NIST) from Michell Instruments' accredited laboratory.

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INSTALLATION

2 INSTALLATION

On delivery, please check that all the following standard components are present in the packing box:

• MDM50

• 2m of 6mm O/D PTFE tube

• Battery charger

• Mains lead

• 3 pole ¼” jack plug (inside lid) - for analog output connections

• User manual

• Certiﬁ cate of calibration

MDM50 LP Version User’s Manual

Before using the MDM50 for the ﬁ rst time it is recommended that the battery pack is charged for a minimum of 12 hours.

The case has a pressure relief valve on the exterior below the handle. When closed, the case is completely sealed. If the instrument is taken through altitude changes, a pressure differential will occur within the case. If this occurs: Before opening the lid, open the black pressure relief valve by one turn (anti-clockwise) for a few seconds. This will equalize the pressures. When the case has been opened, ensure that the pressure relief valve has been fully closed.

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MDM50 LP Version User’s Manual

3 OPERATION

Maximum operating pressure is 20 barg (290 psig).

It is important that the gas ﬁ ttings are correctly tightened, and

any tubing is secure in the push ﬁ ttings before use.

Failure to do so will affect the instrument's pressure rating.

3.1 General Operation

To operate the MDM50, follow these instructions:

OPERATION

1. Ensure that all gas ﬁ ttings are fully tightened before use.

2. Gas under test should be restricted to ﬂ ow rates between 1 and 5 Nl/min (2 and 10.6 scfh) and pressures from atmospheric to 2 MPa (20 barg (290 psig)).

3. Connect the sample gas supply line to the instrument

4. Connect the sample gas vent line to the instrument

5. Switch the instrument on. The display will begin to change as the sensor responds to the applied dew point.

6. Allow the gas to ﬂ ow until the display shows a stable reading. Typically this would be around 5 to 15 minutes for spot checks at dew points of

-40°C (-40°F) and above.

7. Switch the unit off and disconnect the sample lines.

NOTE: Filters are essential for potentially dirty/contaminated gases – the ﬁ tted ﬁ lter should be checked before and after use and replaced regularly - as required.

Gas In port.

Gas Out port.

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OPERATION

MDM50 LP Version User’s Manual

3.2 Atmospheric or Line Pressure Measurements

The MDM50 is supplied with two labelled, interchangeable, gas inlet/outlet ﬁ ttings.

Number Description

1 4mm free ﬂ ow ﬁ tting 2 0.4mm restricted ﬁ tting

Figure 1

Gas Out

LINE PRESSURE

Gas Out

ATMOSPHERIC

Filter Fitted

Interchangeable Gas Inlet/Outlet Fittings

Gas In

In order to perform measurements at line pressure, the restricted ﬁ tting should be on the gas outlet port.

To perform measurements at atmospheric pressure, the restricted ﬁ tting should be on the gas inlet port.

The Gas In port is ALWAYS on the right hand side.

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MDM50 LP Version User’s Manual

3.3 Measuring Dew Points Below -40°C (-40°F)

Due to the signiﬁ cantly lower levels of moisture present at dew points of this level, and the increased amount of time to dry the system out, the response times of the sensor will be signiﬁ cantly 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 (50°Fdp) ambient):

OPERATION

Target Dew Point

°C °F

-30 -22 5

-40 -40 15

-50 -58 30

T100 Response Time

(mins)

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