IR24 (Types MWG 2491 and MWG 2492) Transmitter for carbon dioxide

Transcription

1 Operation Manual IR24 (Types MWG 2491 and MWG 2492) Transmitter for carbon dioxide GfG GESELLSCHAFT FÜR GERÄTEBAU MBH KLÖNNESTRASSE DORTMUND TELEPHONE / FAX / INFO@GFG-MBH.COM AMTSGERICHT DORTMUND HR B 2742 CERTIFIED TO DIN EN ISO 9001:2008 ATEX QM CERTIFICATION

2 Table of Contents Page For your safety 3 General Description 3 Operating instructions 4 Unit design 4 Measurement procedure 4 Installation location of the transmitter 5 Installation 5 Installing electrical connections 6 Commissioning 6 Control of the electrical zero point 7 Checking the display sensitivity 8 Servicing 10 Maintenance and inspection 10 Fault - cause - remedy 10 Connection plans for transmitters on gas measurement computer (GMA) 11 IR24 type MWG IR24 type MWG Terminal assignment plan 12 Technical specifications 12-2-

3 M E N U 1 0 C H A N N E L 8 0 o u t / N 6 0 A 3 i n / M A A 1 U 2 0 % O N F A U L T T U E S T Q U I T M E N U M E N U A 3 A 2 F A U L T For your safety According to Article 3 of the Technical Working Materials Act (Gesetz über technische Arbeitsmittel), this operating manual points out on the intended use of the product and serves to prevent risks. It must be read and followed by all persons that utilise this product or use, service, maintain, and control it. This product can only perform its duties for which it is intended, when it utilised, used, maintained, serviced and controlled according to the instructions given by the GfG company. The warranty provided by the GfG company becomes null and void if it is not used, maintained, controlled or serviced according to the instructions issued by the GfG company. The above does not alter the information on warranty and liability in the terms and conditions of the GfG company. General Description A fixed gas warning system consists of a transmitter (MWG) and a gas measurement computer (GMA). Transmitter and gas measurement computer are connected via a remote sensor cable. The transmitter converts the unit of "gas concentration" into an electrical signal for measuring and sends it via the remote sensor cable to the gas measurement computer for further processing. Fixed gas measurement and warning system 5 Vol% CO2 A 1 Evaluation Auswerten Alarmieren Warning Measurement Messen Figure 1 The transmitter IR24 is an "intelligent" measuring head. Its extensive electronic system takes over many tasks that facilitate the operation and maintenance and also significantly increase the reliability and accuracy. The transmitter IR24 is characterised by: Latest infrared measuring technique (IR) for high reliability and long service life Simple calibration on site Service lid for adjusting zero point and sensitivity Thermostatic control of the measuring cell for compensating temperature influences -3-

4 Operating instructions According to the national regulations, gas warning devices must be inspected for proper functioning by an expert after installation, but before any measuring operation is carried out (commissioning). In Germany the following applies: Regulation for the prevention of accidents, gases 56(2) "UVV Gase" (BGV B6 formerly VBG 61). The transmitter IR24 has been tested for correct operation and display prior to delivery. The calibration was carried out with appropriate testing gases. This does not absolve from a functional testing after installation. Unit design The unit design of the transmitter IR24 is shown in figure 2. Transmitter IR24 unit design Gehäuseoberteil Casing top (Deckel) Gehäuseunterteil Casing bottom 5 Vol % CO2 Messbereich Detection range Messgas Gas Befestigungsschraube Lock screw for für die service Serviceklappe lid Serviceklappe lid Cable Messkabeldurchführung gland PG PG-Verschraubung screwing Diffusionsfläche inlet Figure 2 The transmitter IR24 consists of a robust metal housing. The diffusion opening is located at the lower end of the housing. Potentiometers (controllers) for adjusting the electric zero point and the display sensitivity (adjustment) as well as test sockets for a display unit for checking the zero point and display sensitivity are located behind the service lid. The main circuit board and the calibrating board are in the housing. The electronic system of the main circuit board converts the measuring signal into the measured value output ma or ma. The operating elements are on the calibrating board. Measurement procedure The infrared measuring cell makes use of the property of gases to absorb light in certain spectral areas. The infrared light emitted through a lamp passes through the measurement -4-

5 section filled with sample gas. Thanks to the sample gas, the radiation energy is weakened through absorption. The absorption of infrared radiation within a certain wavelength area in the sample gas depends on the concentration of the gas to be measured. The energy decrease of the infrared radiation caused by absorption is measured with the help of detectors. Installation location of the transmitter In determining the place of installation, it is important to know the environmental conditions and to take them into account when selecting the location, e.g. the ventilation conditions the fact that the density of carbon dioxide (CO 2 ) is higher than the one of air. Thus, gas gathers at ground level. The transmitter IR24 must be installed in the room so that the gases reach the sensor even with unfavourable ventilation. If necessary, a measurement must be made for example with smoke tubes. Outside influences are also to be noted: Rain water, splash water, dripping water, condensation and the dust in the atmosphere. The transmitter IR24 is largely protected against the ingress of water and dust (IP 54). In very difficult conditions, special accessories can be used to protect the transmitter IR24 from damage. GfG will be happy to advise you on appropriate measures.! If the measuring chamber is exposed to environmental conditions which were not known to GfG during planning or delivery, the warranty may become invalid. In determining the place of installation ensure that the transmitter is accessible for service and calibration work. For reasons of easy servicing, the transmitter must be positioned vertically with the sensor pointing downward. Another installation position does not influence the measurement accuracy. Installation The transmitter IR24 is connected to the gas measurement computers according to the terminal assignment (page 12) and connection plans IR24 (page Fehler! Textmarke nicht definiert.). For mounting, unscrew the four special screws (pos. 9, figure 2) and remove the housing cover. The housing is fastened through two boreholes.! The transmitter IR24 is not approved for operation in potentially explosive atmospheres. -5-

6 Installing electrical connections The laying of cables and connection of the electrical installation may only be carried out by an expert taking into consideration the relevant provisions. Depending on the version or type of operation of the transmitter IR24, installation has to be done with a triple or multi-wired shielded cable (e.g. LIYCY 3 x 1.5mm 2 ). The cross-section depends on the length of the connection cable. For short distances (until 200 m), a wire cross-section of 0.75 mm 2 instead of 1.5 mm 2 is sufficient. The shielding is to be placed on the PG cable gland. If a power supply unit or another system is used for operating the transmitter, its operating voltage must not exceed 24 V. After installation, the cover must be closed and screwed again. The transmitter may only be installed and opened when it is free from any gas. Wiring scheme transmitter IR brown green white 24V Ground ma ma GMA Figure 3 Commissioning After mounting and installing the transmitter IR24, its commissioning can be done by an expert. The IR24 has been calibrated and checked in factory. Calibration work performed in factory is done after a run-in period of the new transmitter lasting several days. This measure results in an optimum basic setting. If the transmitter is switched on again, the infrared sensor required a certain run-in period which might last approx minutes until calibration check. -6-

7 Control of the electrical zero point Upon delivery, the transmitter IR24 is checked and calibrated. However, deviations can occur dependent on the transport, installation and environmental conditions. Caution: The electric zero point can only be set in 100 vol.% nitrogen or synthetic air which is free from CO 2. The transmitter requires a run-in period of 30 minutes. If the zero point calibration is done earlier, the sensor setting performed in factory will be falsified. After a run-in period of 30 min. the test sockets (U M ) behind the service lid of the IR24 (figure 4) and the gas measurement computer can be used to connect and read a voltmeter (please refer to the operating instructions of the GMA gas measurement computer). Transmitter IR24 circuit board Sicherung Fuse SI1 SI1 Service switch Serviceschalter SERVICE OPERATION BETRIEB Klemmleiste Terminal bar Potentiometer" ZEROPOINT NULLPUNKT" Test Prüfbuchse socket UM für for volt Voltmeter Potentiometer CALIBRATION "KALIBRIEREN" PG Verschraubung screwing IR - Sensor Figure 4 While setting the zero point, the service switch should be adjusted to "SERVICE" position. -7-

8 The following flowchart describes the procedure for checking the electric zero point: Open the service lid on IR24. Use a calibration adapter for feeding zero gas into the measuring chamber (100 vol% N 2 or synthetic air free from CO 2 ). The flow rate should amount to approx. 0.5 l/min. Service switch in "SERVICE" position Connect the voltmeter to the test socket U M (refer to figure 4) U M = 0.2 V? yes no Adjust the voltage on "ZERO POINT" potentiometer to 0.2 V. Service switch in "MEASURING MODE" position Close the service lid on IR24. Check U N at GMA gas measurement computer. U N should amount to 0 V. Deviations can be adjusted at the GMA gas measurement computer. Please refer to the operating instructions of the GMA gas measurement computer. Checking the display sensitivity For checking the display sensitivity, a test gas adapter has to be plugged in or screwed on the sensor holder. Afterwards, select a suitable test gas. You will need to check first which test gas has been used for setting the transmitter. For the gas type and the measurement range please refer to the test report and the information plate on the transmitter. The value of test gas concentration should amount to a value which is at least 20 % above the second alarm level. For the basic setting of the alarm level and the gas indicator, please refer to the test report of the transmitter. Caution: The display sensitivity can only be adjusted with a suitable test gas. The transmitter requires a run-in period of 30 minutes. If the display sensitivity is modified earlier, the sensor setting performed in factory will be falsified. While checking the display sensitivity, the service switch should be adjusted to "SERVICE" position. The following flowchart describes the procedure for checking the display sensitivity: -8-

9 Serviceklappe Open service am lid IR24 at IR24. entfernen. Kalibrieradapter Fix calibration am adapter IR24 befestigen. at IR24. Serviceschalter switch in in Position position "SERVICE" SERVICE. Prüfgas Supply drucklos test gas mit without einem Durchfluß pressure, von at etwa a flow 0,5 rate l/min of dem approx. IR24 zuführen. 0.5 l/min, Prüfgas to IR24. ist ein Test CO2-Luft- gas is oder a COCO2-Stickstoff-Gemisch 2 /air or 2 /nitrogen mit mixture einer CO2 with Konzentration a CO 2 concentration die dem Meßbereichendwert equivalent to full entspricht scale oder or at mindestens least 20 % 20 % above oberhalb the der 2. alarm 2 Alarmschwelle threshold. liegt. Die Within Anzeige approx. am Gasmesscomputer 1 minute the display muß sich at the innerhalb GMA controller von etwa 1 min must entsprechend show the test dem gas Wert concentration. der Prüfgaskonzentration Should you eingestellt operate haben. the MWG Wird without der MWGMA, G ohne you GMA can betrieben, see the so voltage können values die Spannungswerte from the calibration der Kalibrierkur curve and ve entnommen measure at und IR24 am output IR24-Ausgang U M. "UM" gemessen werden. Gemessener Is the measured W ert stimmt value equivalent mit dem Wert to der the Kalibrierkurve value in the überein? calibration curve? Yes ja nein No An Adjust dem IR24 calibration bzw. dem point Gasmesscomputer at IR24 or at den the Kalibrierpunkt controller. Please nachjustieren. refer to Beachten the operation Sie bitte die manual Betriebsanleitung of your GMA. des Gasmesscomputers. Serviceschalter switch in in Position position "MESSBETRIEB" OPERATION. Serviceklappe Close service am lid IR24 at IR24. schließen. Prüfgas Disconnect und Kalibrieradapter test gas and calibration entfernen. adapter. -9-

10 Servicing In the sense of the regulation for the prevention of accidents, gases "UVV Gase" and according to DIN 31051, servicing includes the maintenance, inspection and repair of gas warning devices. The data sheet T023 published by the German Association of the Chemical Industry (BG Chemie) describes adequate measures as e.g. the periodical performance of a functional testing. This functional testing includes: Checking with alarm gas Zero point and sensitivity (calibration) Time setting Gas sampling system, gas treatment (if applicable) Triggering of warning signals Signalling unit for malfunctions This check has to be performed by an expert. The result has to be confirmed in writing. The calibration intervals shall normally not exceed 16 weeks. The functional testing has to be performed prior to commissioning and at least once a year. Maintenance and inspection Maintenance and inspection include all measures for maintaining the nominal state of the gas warning system. The transmitter IR24 does not require any special maintenance. However, a few aspects should be taken into consideration. Depending on the environmental conditions, gas warning systems can behave differently. Thus, it is important to perform a visual inspection each day in particular within the first few days after commissioning (refer to T023). Checking the gas treatment, the filter units if applicable. Checking the gas supply for contamination. For assuring a correct measurement, the gas supply must be free from any debris. Measuring cells (sensors) get worse and wear out with increasing age. Depending on type and gas admission, there is more or less load on the sensors such that the sensitivity can only be checked with an appropriate test gas during a time period to be determined. The calibration of sensitivity is a professional calibration which is normally performed by the GfG Customer Service or an authorized person. Fault - cause - remedy Fault Cause Remedial action Zero point can no longer be set Sensor defective Replace sensor Final value can no longer be set Sensor defective Replace sensor Output current has dropped to 0 ma Defective fuse Line disconnected Replace fuse Re-connect -10-

11 Connection plans for transmitters on gas measurement computer (GMA) IR24 type MWG 2492 brown green white V GND 4 20 ma GMA GMA GMA GMA81 (A) IR24 type MWG 2491 brown green white V GND ma GMA GMA GMA with bus board from year of manufacture 97 (blue) GMA with bus board to year of manufacture 96 (colourless) GMA GMA GMA81 (A)

12 Terminal assignment plan U= 18,0 V - 24,0 V R1 I = 4-20 ma MWG 2492 MWG 2491 Max. load 150 Ohm Use shielded cable for distances of more than 5 m Technical specifications Transmitter IR24 Transmitter type: MWG 2491 and MWG 2492 Measurement principle: Infrared (IR) Measurement gas: Carbon dioxide (CO 2 ) Measurement range: 1, 2, 5, 10, 15, 20, 25, 50, 70 vol.% (partial pressure measurement) Gas supply: Diffusion No significant influence on measuring signal when using the calibration adapter with l/min. Response time t 90 : 25 s Expected service life of sensor: > 5 years Climatic conditions Storage temperature: C Operating temperature: C Humidity: %r.h. non condensing Air pressure: kpa (100 kpa = 1000 mbar) Electrical connections Supply voltage: V DC Power consumption : < 150 ma (temporarily 200 ma) Output signal in measuring 0,2..1 ma or ma mode: Output signal in service mode: 0..0,2 ma or 0..4 ma with 2Hz pulsating Max. load: ma or ma Technology for people and the environment _OM_IR24_CO2.doc State: December 15, 2015 Subject to change GfG Gesellschaft für Gerätebau mbh Klönnestraße 99 D Dortmund Telephone: Fax: info@gfg-mbh.com Internet:

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