WM33 & 52 User`s Manual
Contents
1. 21 Appendix Recommended Practices in Humidity Measurements 23 Appendix E Return Document amp Decontamination Declaration 28 iV 97240 Issue 3 1 October 2014 WM33 amp 52 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 instruments are designed to be completely safe when used with options and accessories supplied by the manufacturer for use with the instrument 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 an2. MICHELL Instruments WM33 amp 52 amp Temperature Transmitter Wall Mount User s Manual 97240 Issue 3 1 October 2014 Please fill out the form s below for each instrument that has been purchased Use this information when contacting Michell Instruments for service purposes un nn e T _ e T ma 0 1 MICHELL Instruments WM33 amp 52 For Michell Instruments contact information please go to www michell com 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 WM33 amp 52 User s Manual Contents ccn LEERE ER V TORE ALERT ee VEM a PLU V Manton nee V EEE RPG RI Re reb One en euer EEE Deere V LO an ba M E EM CM UE vi UU UNV ce are arte M Vi re m 1 NE cuc RTL mS 1 VEMM ig ic mmm mS 1 2 UN TAEAO n E aigen 2 Beca Cone gt gt A 2 I 3 3 1 Calibration
3. For example the difference between 50 RH and 52 RH is 2 RH This can also be expressed as a difference of 4 of value It is important to distinguish clearly between these two kinds of statement Recommendations specific to ranges of measurements Ambient humidity Avoid using hygrometers near the body which is a source of heat and moisture Do not breathe close to the measurement High humidity above the ambient range Ample lines should be maintained above the dew point of the gas being measured to avoid condensation Electrical trace heating is often the most practical method Low humidity and very dry gases If possible prepare for measurements by flushing sample lines and hygrometers with dry gas or by evacuating to low pressure Drive off stray residual water by baking assemblies if possible but not instruments unless designed for this The lower the moisture content to be measured the more dramatically the required drying time multiplies Avoid hygroscopic materials At low humidity anything much below a dew point of 0 the amounts of water given off by organic and porous materials can dramatically affect the value of humidity The lower the level of moisture the more significant the effects Choose impermeable materials to avoid inward diffusion of moisture through sampling tubes and enclosures Steel and other metals are practicallyimpermeable PTFE Teflon is only slightly permeable and w
4. amp Adjustment for 3 Accuracy ipt Adjustment 4 3 2 Calibration amp adjustment for 2 accuracy 2 pt adjustment 6 3 3 Calibration and Adjustment for Digital Board 8 Figures Figure 1 TLLA AC e io LEN TT 1 Figure 2 COMIC CHONG KR Tm 2 Figure 3 WIEN ONE HN ee i E eee ee E een ee icq 4 Figure 4 OC N 5 Figure 5 we CORDECHON RM t 6 Figure 6 52 3 4 wire 4 Figure 7 3 4 Wire with Display 8 Figure 8 PEN NG ne ee A er T ne 11 Figure 9 si RR 12 Appendices Appendix A Technical SPEEITIESEIOTIS Serena ea nen 10 1 BIRD ETE 11 Appendix B EC Declaration of Conformity ea ee 14 B 1 14 B 2 EE A EE GUN VS IESUS PEA 15 B 3 WMS With ISD Ay 16 Appendix C Quality Recycling amp Warranty Information a 18 1 Pressure Equipment Directive PED 97 23 EC 18 C 2 POC een 18 C 3 WEEEK AI eae EEEE EAE E EEEE 18 4 19 5 NP PEN 19 C 6 REACH COMDBISPOB saxi 20 C 7 ENDE LION FACIO 20 8 ROLL PONY DIMUS 21 9 Manufacturing
5. e g by fast flow rates of gas long exhaust tubes after the sensor or by valves which isolate the low humidity region from ambient air 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 Where a sensor is at risk of exposure to dust droplets or the occasional knock during handling the appropriate guard or filters for the sensor head should be used Any temptation to breathe on the sensor or to wave it over cups of tea etc should be resisted Filters and saturation guarding may protect the sensor but these actions carry a risk of damage by condensation or other contamination Protective filters can slow the response time of sensors This can be avoided by removing any filter but the benefit must be weighed against the risk of damage to the sensor Sensors should not normally be submerged in liquids In the case of a resistive electrolytic sensor water or other liquids would certainly damage the sensor beyond repair Salt solutions are especially commonly used for calibration of electrical sensors and should be provided with traceability directly or via a calibrated hygrometer Protection of sensors from direct contact with salt or solution is most important as contamination woul
6. 2 lt 2 RH 10 90 RH Humidity WM33 lt 3 RH 30 80 WM33 0 3 C 0 5496 Response time RH Sensor lt 10 sec typical for 90 of the step change Electrical output input Output Signal 4 20 mA 0 1 0 5 0 10 V 14 30 V DC 0 5 0 10 V output puppy Voltage 5 30 V DC 0 1 V amp 4 20 mA output Operating conditions Operating Humidity f Probe Housing Storage 5 95 RH non condensing Operating Temperature Probe Housing 30 to 85 C 22 to 185 F With display 20 to 70 C 4 to 158 F Storage 40 to 85 C 40 to 185 F With display 30 to 80 C 22 to 176 F 10 97240 Issue 3 1 October 2014 WM33 amp 52 User s Manual APPENDIX A A 1 Dimensions 50 0 mm 1 97 ex of lt EG ex S G LO eo EN c C 18 5 mm 17 0mm 0 75 0 66 Figure 8 Dimensions Michell Instruments 11 APPENDIX A WM33 amp 52 User s Manual 50 0 mm 1 97 C Mounting 65 0 mm 2 55 This drawing is actual size and can therefore be photocopied and used as a template when mounting the instrument Figure 9 Template 12 97240 Issue 3 1 October 2014 WM33 amp 52 User s Manual APPENDI X B Appendix B EC Declaration of Conformity Michell Instruments 13 APPENDI X WM33 amp 52 User s Manual Appendix B EC Declaration of Conformity B 1 WM33 d MICHELL Instru
7. 2 Circuitboard TERMINAL 1 TEMPERATURE RANGE 0 to 50 C 32 to 122 F 0 to 100 C 32 to 212 F 20 to 80 C 4 to 176 F Soldered joint Figure 5 WM52 2 wire Connection 6 97240 Issue 3 1 October 2014 WM33 amp 52 User s Manual CALIBRATION 3 4 wire Volt Analog CONNECTIONS TERMINAL 5 TERMINAL 4 Also possible is a temperature element between terminal 1 and 2 TERMINAL 2 TERMINAL 3 TERMINAL 2 Circuitboard TERMINAL 1 REL HUMI DI TY OUTPUT Soldered joint Figure 6 WM52 3 4 wire Connection Michell Instruments 7 CALIBRATION WM33 amp 52 User s Manual 3 3 Calibration and Adjustment for Digital Board Version 3 4 wire Volt with display Digital CONNECTIONS V TERMINAL 4 Abs Humidity OUT TEMP TERMINAL 1 Circuitboard With SW1 you can toggle the display between GND TERMINAL 2 2 lines of characters 7 x 14 dots Temp and RH 4 lines of characters 5 x 7 dots Temp RH Dew Point and Absolute Humidity Figure 7 3 4 Wire with Display Connection For calibration and adjustment contact your local Michell Instruments distributor 97240 Issue 3 1 October 2014 WM33 amp 52 User s Manual APPENDIX A Appendix A Technical Specifications Michell Instruments 9 APPENDIX A WM33 amp 52 User s Manual Appendix A Technical Specifications Measurement Range RH 0 100 RH Measurement Range T 20 to 809 4 to 176 F WM5
8. 2006 Registration Evaluation Authorisation and Restriction of Chemicals REACH Michell Instruments is a manufacturer of moisture measurement and gas analysis instrumentation and is a downstream user of chemicals as described by the EU Council Directive 76 769 EEC The products we supply are not raw chemical products goods Under normal and reasonably foreseeable circumstances of application the goods supplied to you shall not contain or release any prohibited chemicals No listed SVHC Substances of Very High Concern appear within products manufactured by Michell Instruments Therefore the 0 1 mass per product or total usage of 1 tonne year will never be exceeded For these reasons we are neither required by obligation for registration nor for the creation of material safety data sheets MSDS for our products 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 In the unlikely event that any chemicals of concern appear in our products in quantities greater than 0 1 of total mass per product we will immediately inform you by correspondence according to the REACH Article 33 requirements Our current appraisal is however that we do not exp
9. EU states the closing date for compliance of any Control and Monitoring 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 Michell Instruments continues to monitor suppliers and material sources to ensure that compliance of goods provided is maintained January 2013 C 5 Warranty Unless otherwise agreed the Supplier warrants that as from the date of delivery for a period of 12 months the goods and all their component parts where applicable are free from any defects in design workmanship construction or materials The Supplier warrants that the services undertaken shall be performed using reasonable skill and care and be of a quality conforming to generally accepted industry standards and practices Except as expressly stated all warranties whether express or implied by operation of law or otherwise are hereby excluded in relation to the goods and services to be provided by the Supplier All warranty services are provided on a return to base basis Any transportation costs for the return of a warranty claim shall reside with the Customer Michell Instruments 19 APPENDIX WM33 amp 52 User s Manual C 6 REACH Compliance Regulation EC No 1907
10. Recycling amp Warranty Information Michell Instruments 17 APPENDIX WM33 amp 52 User s Manual Appendix C Quality Recycling amp Warranty Information 1 Pressure Equipment Directive PED 97 23 EC The above Directive has been implemented in United Kingdom Law by the Pressure Equipment Regulations 1999 The Regulations require that all pressure equipment and assemblies within the scope of the Pressure Equipment Directive must be safe when placed on the market or put into service Michell Instruments products have been assessed and as referenced against the Classification Charts detailed in Annex II of the Directive do not fall into the requirements for CE marking compliance with the Pressure Equipment Directive Article 3 paragraph 3 states that any product containing a pressurized fluid that does not qualify for compliance should nevertheless be constructed with Sound Engineering Practice SEP Michell Instruments attests here that its products have been designed manufactured amp tested to assure safe operation and in accordance with Sound Engineering Practices 4 2 Recycling Policy Ta 2 Michell Instruments is concerned with the protection of the environment It is our commitment to reduce and eliminate from our operations wherever possible the use of substances which may be harmful to the environment Similarly we are increasingly using recyclable and or recycled material in our business and pr
11. ate the product to determine the cause of the malfunction Then one of the following courses of action will be taken If the fault is covered under the terms of the warranty the instrument will be repaired at no cost to the owner and returned If Michell Instruments determines that the fault is not covered under the terms of the warranty or if the warranty has expired an estimate for the cost of the repairs at standard rates will be provided Upon receipt of the owner s approval to proceed the product will be repaired and returned 9 Manufacturing Quality Michell Instruments is registered with the British Standards Institute for Quality Assurance to BS EN ISO 9001 2008 Rigorous procedures are performed at every stage of production to ensure that the materials of construction manufacturing calibration and final test procedures meet the requirements laid down by our BSI approved Quality System Please contact Michell Instruments www michell com if the product does not arrive in perfect working order Michell Instruments 21 APPENDIXD WM33 amp 52 User s Manual Appendix D Recommended Practices in Humidity Measurement 22 97240 Issue 3 1 October 2014 WM33 amp 52 User s Manual APPENDIX D Appendix D Recommended Practices in Humidity Measurements The following text is reproduced with kind permission from the National Physical Laboratory It is originally published in the booklet A Guide to the Mea
12. ation declaration Decontamination Declaration 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 MICHELL F0121 Issue 2 December 2011 Instruments 28 97240 Issue 3 1 October 2014 WM33 amp 52 User s Manual NOTES Michell Instruments 29 Messtechnik A 8010 Graz Riesstra e 146 ELEKTRONIK Tel 43 316 40 28 05 Fax 40 2506 Handelsgesellschaft m b H MICHELL Instruments http www michell com
13. content of the gas being measured What is more condensed liquid may alter the humidity elsewhere by dripping or running to other locations and evaporating there In these circumstances measurement results may be misleading if hygrometer location is not considered carefully Water droplets or mist must be avoided These can result overestimates of the humidity of the air between the droplets Such results may exceed 100 RH or may be impossible to interpret meaningfully Droplets of liquid also damage some electrical types of humidity sensor Filtering the air sample can eliminate droplets If pumps are used for sampling gas these should be located after the hygrometer to avoid contaminating the measurement environment Where possible oil free pumps should be used or filters employed Oscillations in pressure due to pumping can sometimes be reduced or buffered using a needle valve or a reservoir of large volume Special treatments such as filtration can change the amount of moisture in a gas Some drying agents take out other gases too When sealing any sensor probe into a port manifold in duct or chamber leaks through the probe or electrical cable should be considered These are not always sealed against passage of ambient air Where sampling involves a step change in temperature pressure or gas flow rate relative to the process being sampled results may need to be converted or interpreted For exampl
14. d 2 O TERMINAL 2 TERMINAL 3 Circuitboard TERMINAL 2 TERMINAL 1 REL HUMIDITY OUTPUT Lo S 5 el o ivoc e o svoc e o tovoc Soldered joint TEMPERATURE RANGE OUTPUT 0 to 50 C 0 to 100 C 20 to 80 C 32 to 122 F 32 to 212 F 4 to 176 F E 101 efe 5 Jeje F tet p le J o vocg je je jeje f jej jo Soldered joint Figure 4 WM33 3 4 wire Connection Michell Instruments 5 CALIBRATION WM33 amp 52 User s Manual 3 2 Calibration amp adjustment for 2 accuracy 2 pt adjustment WM52 1 Unscrew the four bayonet screws on the front panel 2 Remove the front panel The transmitter should calibrated at two points one low Zero and one high Span point Once the first low value is reached and reading of reference is stabilized adjust the transmitter with the Zero RH potentiometer Compare with the reference After the second high value is reached and stabilized adjust with the Span RH potentiometer For versions with a T output this procedure should be repeated with a temperature potentiometer only use the Zero temp potentiometer to adjust the temperature readings See Figure 5 for 2 wire 4 20 mA output and Figure 6 for 3 4 wire voltage output 0 1 0 5 or 0 10 V 2 wire mA Analog TERMINAL TERMINAL 4 TERMINAL 2 TERMINAL 1 TERMINAL
15. d Maintenance The instrument must be maintained either by the manufacturer or an accredited service agent For Michell Instruments worldwide offices contact information go to www michell com Calibration Michell Instruments recommends annual calibration for an accuracy requirement of 290 under ambient conditions where temperature is 0 to 50 C 32 to 122 F and relative humidity is to 70 RH For environments with airborne chemicals for high humidity and high temperature conditions Michell recommends more frequent calibration 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 specification EMC Compatibility The WM33 amp 52 relative humidity amp temperature transmitters are designed to meet the following European standards EN 61326 1997 1 1998 A2 2001 e 61000 3 2 1995 1 1998 A2 1998 amp EN 61000 3 3 1995 Emission Class Immunity Industrial Michell Instruments V WM33 amp 52 User s Manual Abbreviations The following abbreviations are used in this manual 4 degrees Celsius OF degrees Fahrenheit DC direct current inch es mA milliampere mm millimeters percentage OZ ounce s RH relative humidity temperature Volts Ohms Warnings The following general warning listed below is applicable to this in
16. d destroy or seriously impair the sensing element 26 97240 Issue 3 1 October 2014 WM33 amp 52 User s Manual APPENDIXE Appendix E Return Document amp Decontamination Declaration Michell Instruments 27 APPENDIXE WM33 amp 52 User s Manual Appendix E Return Document amp Decontamination Declaration Decontamination Certificate 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 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 Radioactive substances 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 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 lt 30 C over 24 hours should be sufficient to decontaminate the unit prior to return Work will not be carried out on any unit that does not have a completed decontamin
17. e pressure dew point will differ from the value found after expanding the gas sample to atmospheric pressure Care should be taken to distinguish between gauge and absolute values of pressure 24 97240 Issue 3 1 October 2014 WM33 amp 52 User s Manual APPENDIX D Dew point in general The measuring environment and all parts of the sampling pathway must be kept above the dew point if condensation is to be avoided Electrical trace heating or other heating methods should be used if necessary An excess temperature of 10 C above the dew point is usually a safe margin For measurements in the region below 0 C it must be clear whether the condensate is dew or frost Failure to distinguish between these can result in errors of about 1 C for every 10 C below zero 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 In many situations the largest single source of uncertainty in a humidity measurement is the effect of temperature differences from place to place in the process room or chamber The importance of considering the temperature effects carefully cannot be overstated when relative humidity is the parameter of interest Care must be taken when expressing uncertainties changes or fractional differences in relative humidity
18. e Before using any solvent cleaner check with Michell Instruments that this will not harm the sensor or other materials of construction Wherever possible ensure that hygrometers are calibrated under the conditions of use i e at similar values of humidity and temperature and if relevant in similar conditions of pressure airflow etc Keep a record of calibrations and any adjustments to the hygrometer This will show the long term stability of the instrument and allow the associated uncertainty to be assessed Check instruments if possible at intervals between calibrations by comparison with another stable instrument to monitor for long term drift Routine checks are also useful before and after subjecting an instrument to transportation or other stress which might lead to a shift in its performance Where the check is against two or more instruments this is even better not only does this add confidence but in the event of one instrument drifting among a set of three it can be seen which reading is most suspect Michell Instruments 23 APPENDIX D WM33 amp 52 User s Manual Cleanliness of the environment will affect different hygrometers in different ways Dust and airborne droplets should be avoided or filtered out if possible Contaminants can come from the most surprising sources ordinary urban pollution for example The readings given by some types of hygrometer are sensitive to gas type For any I
19. ect or foresee such an incidence January 2013 C 7 Calibration Facilities Michell Instruments calibration facilities are among the most sophisticated in the world and have been recognized for their excellence Traceability to the National Physical Laboratory NPL UK is achieved through our UKAS Accreditation Number 0179 This covers dew point over the range 90 to 90 130 to 194 F and also Relative Humidity Dew point calibrations are also traceable to the National Institute for Standards amp Technology NIST USA over the range 75 to 20 C 103 to 68 F NOTE Standard traceable calibration certificates for instruments and sensors are not issued under our UKAS accreditation UKAS certificates are usually to special order and are clearly identified 20 97240 Issue 3 1 October 2014 WM33 amp 52 User s Manual APPENDIX 8 Return Policy If a Michell Instruments product malfunctions within the warranty period the following procedure must be completed 1 Notify a Michell Instruments distributor giving full details of the problem the model variant and the serial number of the product 2 If the nature of the problem indicates the need for factory service then the instrument should be returned to Michell Instruments carriage prepaid preferably in the original packaging with a full description of the fault and the customer contact information 3 Upon receipt Michell Instruments will evalu
20. ill usually be satisfactory for dew points above 20 C and sometimes below this level Materials such as PVC and rubber are relatively permeable and so totally unsuitable at low humidity and not really satisfactory in any humidity range Surface finish of pipework is important for very dry gases Even tiny quantities of water adsorbed on the surfaces of non hygroscopic materials can have significant effect Polished or electropolished steel is recommended for the best results Michell Instruments 25 APPENDIX D WM33 amp 52 User s Manual Clean environments are always best for humidity measurements but this is especially critical at very low humidity Even fingerprints harbour water High purity cleaning agents are recommended Analytical Reagent AR quality solvents for oil based contaminants and purified water distilled or de ionised for salts Cleaning should be followed by thorough drying by a clean method Sample tubing should be as short in length as possible The surface area should be minimised by using the narrowest tubing that the flow conditions will permit Avoid leaks Minimising the number of connections elbows tees valves etc helps with this Adequate flow of the gas sample should to minimise the influence of sources of stray water in the flow path Dead ends should be avoided as they cannot easily be flushed Back diffusion of moisture should be minimised
21. ions and immunity and has been designed to be in conformance with the relevant sections of the following standards or other normative documents EN61010 1 2010 Safety Requirements for Electrical Equipment for Measurement Control and Laboratory Use Part 1 General Requirements Peter Haakma Managing Director Michell Instruments B V Date of Issue November 2012 Michell Instruments 15 APPENDI X WM33 amp 52 User s Manual B 3 WMB52 with Display EC Declaration of Conformity m MICHELL WM32 with Display RH amp Temperature Transmitter Manufacturer Michell Instruments B V Krombraak 11 4906 CR Oosterhout Netherlands We declare under our sole responsibility that the product complies with all the essential requirements of the EC directives listed below 2004 108 EC EMC Directive Using the standards EN61326 1 2006 Electrical equipment for measurement control and laboratory use EMC requirements Group 1 Class B emissions and immunity and has been designed to be in conformance with the relevant sections of the following standards or other normative documents EN61010 1 2010 Safety Requirements for Electrical Equipment for Measurement Control and Laboratory Use Part 1 General Requirements Peter Haakma Managing Director Michell Instruments B V Date of Issue November 2012 16 97240 Issue 3 1 October 2014 WM33 amp 52 User s Manual APPENDIX Appendix C Quality
22. ments Manufacturer Michell Instruments B V Krombraak 11 4906 CR Oosterhout Netherlands We declare under our sole responsibility that the product EC Declaration of Conformity WM33 RH amp Temperature Transmitter complies with all the essential requirements of the EC directives listed below 2004 108 EC EMC Directive Using the standards EN61326 1 2006 Electrical equipment for measurement control and laboratory use EMC requirements Group 1 Class B emissions and immunity and has been designed to be in conformance with the relevant sections of the following standards or other normative documents EN61010 1 2010 Safety Requirements for Electrical Equipment for Measurement Control and Laboratory Use Part 1 General Requirements Peter Haakma Managing Director Michell Instruments B V Date of Issue November 2012 14 97240 Issue 3 1 October 2014 WM33 amp 52 User s Manual APPENDI X B 2 WM52 MICHELL Instruments Manufacturer Michell Instruments B V Krombraak 11 4906 CR Oosterhout Netherlands We declare under our sole responsibility that the product EC Declaration of Conformity m WMS32 RH amp Temperature Transmitter complies with all the essential requirements of the EC directives listed below 2004 108 EC EMC Directive Using the standards EN61326 1 2006 Electrical equipment for measurement control and laboratory use EMC requirements Group 1 Class B emiss
23. nstrument which reads in terms of mass per unit volume e g in grams per cubic metre it must be confirmed whether the calibration is valid for the gas in use 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 Failure to allow temperature equilibration will lead to a false indication of the relative humidity Variations in vapor pressure from place to place can occur where an environment is subject to any addition or removal of water If so care must be taken over where to make a measurement in order to obtain a representative result Sources and sinks of water vapor should avoided in sampling system Invasion of stray water can be minimised by attention to leaks hygroscopic materials droplets and condensation The lower the humidity the more critical these precautions are Hygroscopic materials should be avoided Many materials contain moisture as part of their structure particularly organic materials whether natural or synthetic salts or anything which contains them and anything which has small pores Temperature changes can increase the tendency of these materials to affect the humidity of the surrounding air Condensation in a sampling process can invalidate humidity measurements by reducing the water
24. oducts wherever it is practical to do so To protect natural resources and to promote material reuse please separate batteries from other types of waste and recycle responsibly If batteries are not properly disposed of these substances can cause harm to human health and the environment The product that you have purchased may contain recyclable and or recycled parts and we will be happy to provide you with information on these components if required For further information please see the following sections C 3 WEEE Compliance Directive 2012 19 EU 4 uly 2012 on Waste Electronic and Electrical Equipment WEEE The Waste Electronic and Electrical Equipment WEEE Directive places rules upon European manufacturers of electrical and electronic equipment 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 JBO235YW and treats the requirement of the directive and the protection of the environment with the utmost importance All Michell Instruments products are appropriately marked indicating their requirement for recycling It may be required to return certain instruments for treatment at the end of their working life Feb 2013 18 97240 Issue 3 1 October 2014 WM33 amp 52 User s Manual APPENDIX 4 RoHS2 Compliance Directive 2011 65 EU of the Eu
25. on with a general reference handheld hygrometer is ideal for a quick and accurate calibration For more information on 5503 S904 or Optical humidity generators please contact Michell Instruments see contact details at www michell com Michell Instruments 3 CALIBRATION WM33 amp 52 User s Manual 3 1 Calibration amp Adjustment for 3 Accuracy Adjustment WM33 1 Unscrew the four bayonet screws on the front panel 2 Remove front panel The transmitter should be calibrated at one point for example 50 Once this value is reached and the reading of the reference has stabilized adjust the transmitter with the RH potentiometer For versions with a T output the temperature should be calibrated at ambient temperature After stabilizing adjust with the temperature potentiometer See Figure 3 for 2 wire 4 20 mA output and Figure 4 for 3 4 wire voltage output 0 1 0 5 or 0 10 V 2 wire mA Analog TERMINAL 3 Also possible is a temperature element between terminal 1 and 2 TERMINAL 1 Circuitboard az TERMINAL 1 TEMPERATURE RANGE 0 to 50 C 32 to 122 F 0 to 100 C 32 to 212 F 20 to 80 C 4 to 176 F Soldered joint Figure 3 WM33 2 wire Connection 4 97240 Issue 3 1 October 2014 WM33 amp 52 User s Manual CALIBRATION 3 4 wire Volt Analog CONNECTIONS TERMINAL 5 TE TERMINAL 4 Also possible is a temperature element between terminal 1 an
26. ropean Parliament and of the Council of 8 J une 2011 The Restriction of Hazardous Substances RoHS Directive places rules upon European manufacturers of electrical and electronic equipment The directives aim is to reduce the impact that electronic devices have on the environment According to the EC Directive 2002 95 EC Michell Instruments products qualify as Category 9 Control and Monitoring Equipment Under the 2002 95 EC Directive Category 9 products are exempt from compliance with the Directive However the careful design of all Michell Instruments products takes into consideration the requirements of the Directive and wherever possible compliance is achieved All future products will be developed entirely using compliant materials Furthermore Michell Instruments is taking active steps to remove non compliant materials and components from existing products wherever these may occur Presently none of the non compliant materials are known to occur in Michell Instruments products The new Directive 2011 65 EU RoHS2 entered into force on 21 July 2011 and required all Member States to transpose the provisions into their respective national laws by 2 January 2013 Under the provisions of the RoHS2 EU Directive 2011 65 EU Article 3 24 defines Control and Monitoring Equipment specifically as monitoring and control instruments designed exclusively for industrial or professional use RoHS2 EU Directive 2011 65
27. strument It is repeated in the text in the appropriate locations Where this hazard warning symbol appears the following sections it is used to indicate areas where potentially hazardous operations need to be carried out vi 97240 Issue 3 1 October 2014 WM33 amp 52 User s Manual INTRODUCTION 1 INTRODUCTION The WM33 amp 52 are wall mounted units that have the ability to display and provide an output signal of RH dew point or absolute humidity and temperature The WM Series offers excellent measurement accuracy and stability wherever a wall mounted sensor is required There are 3 versions available WM33 analog WM52 analog without display WM52 digital with or without display Figure 1 WM33 amp 52 1 1 Highlights WM33 is designed for low cost HVAC applications 52 with display has digital technology and is designed for accurate measurements in a controlled environment Easy to calibrate to maintain high accuracy 1 2 Features RH dew point absolute humidity and temperature outputs WMB2 user selectable 2 line or 4 line display version Easy to re calibrate Long term stability 1 RH over 12 months Quick installation Michell Instruments 1 INSTALLATION WM33 amp 52 User s Manual 2 INSTALLATION 2 1 Electrical Connections 3 4 wire voltage output with display DC power supply 3 4 wire voltage output 2 wire mA output DC power
28. supply DC power supply Pin 1 Pin 1 Pt100 Pt1000 Pt100 Pt1000 Pin 1 Output temperature Pin2 ground Output RH Dew Point Absolute Humidity Power supply V Output temperature Pin 1 Output temperature Common ground Pin 2 Output temperature Output RH 3 Output RH Power supply V Pin 4 Output RH PT direct and Temperature output versions Pin 2 ma PT direct and Temperature output versions Figure 2 Electrical Connections 2 97240 Issue 3 1 October 2014 WM33 amp 52 User s Manual CALIBRATION 3 CALIBRATION Calibration certifications In addition to normal calibration procedure each transmitter can be supplied with its own traceable calibration certificate Please ask Michell Instruments or your local distributor for more information Calibration interval time Under normal ambient conditions 0 to 50 C 0 to 70 and for accuracy of 2 annual calibration 15 recommended For accuracy of 5 calibration is recommended every five years For environments with airborne chemicals or of high humidity and high temperature conditions more frequent calibration is recommended If re adjustment is necessary refer to Sections 3 1 3 2 and 3 3 and also see the drawings of the circuit boards for the location of the potentiometers Figures 3 to A humidity generator Michell Instruments S503 S904 or Optical used in combinati
29. surement of Humidity Definition of Relative Humidity Relative Humidity The ratio of the actual vapor pressure to the saturation vapor pressure over a plane liquid water surface at the same temperature expressed as a percentage This is commonly understood when the term X percent relative humidity is used For actual vapor pressure e and saturation vapor pressure e e relative humidity in 90 x 100 e S USAGE The phrase relative humidity is commonly abbreviated RH although this is not a recognized abbreviation Values of relative humidity are commonly expressed in units of percent relative humidity RH Recommended practices in humidity measurements General practical recommendations Where relative humidity is of interest a direct measurement of relative humidity is usually best Where an absolute measure of humidity is needed choose dew point vapor pressure or similar measurements Establish the measurement requirements at the purchasing stage in order to have the right instrument for the job Allow hygrometers to equilibrate in any new environment This is particularly necessary after changes in temperature due to transportation or storage Depending on the instrument and on how great the change in conditions this may require from only a few minutes to many hours Follow Michell Instruments care instructions for the instrument Some instruments need routine cleaning or other maintenanc
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