Michell Instruments WM281 User Manual

Premium wall mount rh & temperature transmitters

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WM281/291

Premium Wall Mount

RH & Temperature Transmitters'

User's Manual

97463 Issue 1

July 2014

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Summary of Contents for Michell Instruments WM281

Page 1 WM281/291 Premium Wall Mount RH & Temperature Transmitters’ User’s Manual 97463 Issue 1 July 2014...
Page 2 Please fill out the form(s) below for each instrument that has been purchased. Use this information when contacting Michell Instruments for service purposes. Transmitter Code Serial Number Invoice Date Location of Instrument Tag No Transmitter Code Serial Number Invoice Date...
Page 3 © 2014 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.
Page 4: Table Of Contents
WM281/291 User’s Manual Contents Safety ..........................vi Electrical Safety ......................vi Toxic Materials ......................vi Repair and Maintenance ....................vi Calibration ........................vi Safety Conformity ......................vi Abbreviations ........................vii Warnings ...........................vii INTRODUCTION ....................1 INSTALLATION ....................3 Unpacking the Instrument ................... 3 Choice of the Site of Installation ................3 Element Filter Assembly ..................
Page 5 WM281/291 User’s Manual Appendices Appendix A Technical Specifications ................14 Appendix B Modbus Holding Register Map ..............16 Current Mapping of Modbus Holding Registers ....... 16 Appendix C Digicor2 280/290 Communications Kit (Optional) ......... 20 Appendix D EC Declaration of Conformity ..............22 Appendix E Quality, Recycling &...
Page 6: Safety
Repair and Maintenance The instrument must be maintained either by the manufacturer or an accredited service agent. For Michell Instruments’ contact information please go to www.michell.com. Calibration Refer to details in Section 3.1.2 regarding recalibration of transmitters in order to adjust their calibration in accordance with reference samples or an external reference device.
Page 7: Abbreviations
WM281/291 User’s Manual Abbreviations The following abbreviations are used in this manual: ampere °C degrees Celsius °F degrees Fahrenheit grams per cubic meter g/kg grams per kilogram kJ/kg kilojoules per kilogram kilometer milliampere millimeter m/sec meters per second relative humidity...
Page 8: Introduction
• PR285 Premium Pressurized Remote Transmitter range This manual is for the WM281/291 versions only. The 280/290 Series Transmitters have two analog outputs for temperature and relative humidity respectively providing 4-20 mA, 0-20 mA, 0-10 V, 0-1 V and 0-5 V. There is a third analog output which is calculated providing 4-20 mA, 0-20 mA, 0-10 V, 0-1 V and 0-5 V.
Page 9 WM281/291 User’s Manual INTRODUCTION Frost point The temperature at which a mixture of gas and water vapor must be cooled (at constant pressure) so that condensation begins in the solid phase, i.e. the temperature at which a gas becomes saturated in equilibrium on a flat surface of ice. The unit of measure is degrees Celsius (°C), or can be set to degrees Fahrenheit (°F).
Page 10: Installation
INstallatIoN INSTALLATION Unpacking the Instrument On delivery please check that all the following components are present in the packing box: • WM281 or WM291 Premium Wall Mount Transmitter • Certificate of calibration • User’s manual • Digicor2 280/290 configuration software and communication kit (optional)
Page 11: Element Filter Assembly
The fi lter allows the sensor to ‘breathe’ the humidity contained in the environment to be measured and it is therefore very important to keep it clean. The WM281/291 Transmitters can be equipped with the following fi lter models: Standard - Delrin cap with steel mesh fi lter for use in environments which are relatively clean and where there is poor ventilation.
Page 12: Connections
Electrical Connections Figure 3 The electrical connection box is located in the main body of the WM281/291 Transmitters. Undo the four screws on the face of the transmitter and carefully lift up the top panel. The connector is located on the circuit board.
Page 13: Digital Serial Interface
Please refer to Appendix B. Analog Output Configuration On the WM281/291 Transmitters, configuration of the three analog outputs can be achieved automatically via the RS485 Modbus interface with the Digicor2 Configuration Software (see Section 4) or on the WM291 manually via the LCD display keypad.
Page 14: Interchangeable Sensor Module
S904 - Humidity calibrator - for calibration purposes • Optical cooled mirror calibrator - for laboratory calibration purposes Certificate of Conformity The WM281/291 Transmitters are delivered with a Certificate of Conformity and a calibration report for each individual transmitter. Michell Instruments...
Page 15: Operation
WM281/291 User’s Manual OPERATION Digital Display and Operation Keys Applicable to WM291 Transmitter only  The WM291 Transmitter can be confi gured manually through the following 8 sub-menus. Press and hold the (Function) key and then single press the  (up) key to allow...
Page 16: Protected Sub-Menus
WM281/291 User’s Manual OPERATION 3.1.2 Protected Sub-Menus These are password protected menus and should only be accessed by trained personnel These are password protected menus and should only be accessed by trained personnel These are password protected menus and should only be accessed by trained personnel...
Page 17 WM281/291 User’s Manual OPERATION RH Calibration • Set RH • Restore factory settings NOTE: Changes to some of these settings may lead to the loss of calibration data and should only be changed by qualified personnel when absolutely necessary. 97463 Issue 1, July 2014...
Page 18: Digicor2 280/290 Configuration Software
AND COMMUNICATIONS KIT For more details refer to Appendix C. Hardware RS485 Installation To reconfigure the set-up of the WM281/291 Transmitters, Communications Kit Digicor2 must have been ordered and this is supplied with the following components: • Configuration Software CD •...
Page 19: Maintenance
Ensure that the appropriate adhesive label (with the date of calibration) is attached to the transmitter housing. Carefully screw the protection filter back on. Michell Instruments delivers each interchangeable module with an identification label which must be attached to the transmitter housing over the previous label.
Page 20 WM281/291 User’s Manual appendix a Appendix A Technical Specifications Michell Instruments...
Page 21: Appendix A Technical Specifications
WM281/291 User’s Manual appendix a Appendix A Technical Specifications Performance Specifications Measurement Range (RH) 0 to 100% RH Measurement Range (T) -30 to +70°C (-22 to +158°F) Accuracy at 23°C (73°F) <±2% RH (5–95% RH) Humidity Accuracy at 23°C (73°F) ±0.4°C (±0.72°F)
Page 22 WM281/291 User’s Manual appendix B Appendix B Modbus Holding Register Map Michell Instruments...
Page 23: Appendix B Modbus Holding Register Map
WM281/291 User’s Manual appendix B Appendix B Modbus Holding Register Map Current Mapping of Modbus Holding Registers Access Decimal Address Parameter Default Unit Description Type Value Value Points Returns present value of Temperature Reading °C/°F temperature channel Returns present value of Humidity Reading 100.0...
Page 24 WM281/291 User’s Manual appendix B Reads Software release number Software Release 6.00 in format X.XX 123 – RESERVED get/Set Analog output type for Temperature Type of Analog 0 = 0 – 20mA output for 1 = 4 – 20mA Temperature 128 = 0 –...
Page 25 WM281/291 User’s Manual appendix B High Limit of Analog get/Set Maximum value of Frost output for Frost Point Point output 190 – RESERVED get/Set Digital Filter value for Digital Humidity Filter 20.0 Seconds Humidity input Humidity Offset Correction get/Set Single Point Calibration -999.0...
Page 26 WM281/291 User’s Manual appendix C Appendix C Digicor2 280/290 Communications Kit (optional) Michell Instruments...
Page 27: Appendix C Digicor2 280/290 Communications Kit (Optional)
The connection details are shown in the connection diagram below: Orange wire to Pin 9 Yellow wire to Pin 10 Updates on all Digicor2 280/290 software are available on www.michell.com through the WM281/291 product page. 97463 Issue 1, July 2014...
Page 28 WM281/291 User’s Manual appendix d Appendix D EC Declaration of Conformity Michell Instruments...
Page 29: Appendix Dec Declaration Of Conformity
WM281/291 User’s Manual appendix d Appendix D EC Declaration of Conformity 97463 Issue 1, July 2014...
Page 30 WM281/291 User’s Manual appendix e Appendix E Quality, Recycling & Warranty Information Michell Instruments...
Page 31: Appendix E Quality, Recycling & Warranty Information
The directives’ aim is to reduce the impact that electronic devices have on the environment. Michell Instruments is in full compliance with the WEEE Directive and is registered with an approved recycler (Registration No. WEE/JB0235YW) and treats the requirement of the directive and the protection of the environment with the utmost importance.
Page 32: Rohs2 Compliance
Equipment product sold into the EU market place as 22nd July 2017. However, the careful design policy of all Michell Instruments’ products continues to attain compliance in the shortest practical timescales and strives to ensure that less than 0.1% of total mass per product, of all non-compliant materials, appear within them.
Page 33: Reach Compliance
Our continued review of the SVHC Candidate List and latest additions is to ensure we remain compliant. Michell Instruments maintains a hazardous material register in which MSDS data sheets are collated, and we will check that our suppliers will comply to REACH requirements for all materials and substances we use in the processes of our manufacturing.
Page 34: Return Policy
WM281/291 User’s Manual appendix e Return Policy If a Michell Instruments’ product malfunctions within the warranty period, the following procedure must be completed: Notify a Michell Instruments’ distributor, giving full details of the problem, the model variant and the serial number of the product.
Page 35 WM281/291 User’s Manual appendix F Appendix F Recommended Practices in Humidity Measurements 97463 Issue 1, July 2014...
Page 36: Appendix F Recommended Practices In Humidity Measurements
• Follow Michell Instruments’ care instructions for the instrument. Some instruments need routine cleaning or other maintenance. Before using any solvent cleaner, check with Michell Instruments that this will not harm the sensor or other materials of construction.
Page 37 WM281/291 User’s Manual appendix F • Avoid using instruments in direct sunlight or near any other source of heat, unless they are suitably shielded to prevent measurement errors. Sampling in general • Relative humidity measurements should be carried out at a representative temperature.
Page 38 WM281/291 User’s Manual appendix F Relative humidity in general • Due care must be taken of temperature. The effect of temperature on humidity is highly significant. Failure to take this into account can sometimes lead to errors so large that the measurement is meaningless.
Page 39 WM281/291 User’s Manual appendix F Practical recommendations for specific types of hygrometer Relative humidity capacitive sensor • Care should be taken to avoid mechanical shock (impact) or thermal shock (sudden temperature changes). Sensors should be protected from steam or water sprays, and from direct sunlight.
Page 40 WM281/291 User’s Manual appendix G Appendix g Return Document & Decontamination Declaration Michell Instruments...
Page 41: Appendix G Return Document & Decontamination Declaration
Has the equipment been cleaned and decontaminated? NOT NECESSARY Michell Instruments will not accept instruments that have been exposed to toxins, radio-activity or bio-hazardous materials. For most applications involving solvents, acidic, basic, flammable or toxic gases a simple purge with dry gas (dew point <-30°C) over 24 hours should be sufficient to decontaminate the unit prior to return.
Page 42 http://www.michell.com...

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