TOXIC GAS AND OXYGEN DETECTOR INSTALLATION, OPERATING AND MAINTENANCE INSTRUCTIONS DTX420_MAN01_EN_V1R2
1 Introduction These instructions must be read carefully by any person who has or will have the responsibility for the installation, the use and/or the maintenance of this equipment. The warranty provided by DALEMANS will be voided if installation, use and maintenance of this equipment are not in accordance with the instructions given in this manual. By respecting these instructions you guarantee the correct operation of the apparatus. Should you require any further information about the use or the maintenance of this product, do not hesitate to contact Dalemans PRIOR to carrying out installation works. Each apparatus must be installed, operated and maintained according to the instructions, the warnings and the operational limits detailed in this manual. Use only Dalemans original parts when you assume the maintenance of this product as specified in this manual. The use of non-dalemans spare parts may seriously impair the performances of the apparatus. Repair or maintenance attempts carried out without observing the procedures described in this manual or without the assistance of our after-sales service may prevent the equipment from working properly and, consequently, from ensuring the safety of the occupants of the building and of the plants. Environment - WEEE directive The crossed-out wheelie bin logo on this product indicates that you are held to respect the regulation in force on the collection and recycling of Waste Electrical and Electronic Equipment (WEEE). These provisions are intended to preserve the natural resources used for manufacturing this product and to avoid the dispersion of substances potentially harmful for the environment and human health. Therefore, to dispose of your end-of-life product, you MUST hand it over to a designated collection point for the recycling of electrical and electronic Equipment. For further information about the collection points in your area, contact your local city office. Quality assurance The products hereby described have been designed, manufactured and controlled within the framework of an ISO9001 certified quality assurance system.
2 Marking The label below is affixed to the sensing head of the detector. This marking applies to the overall detector assembly. Device type Measuring range Sensor type Electrical characteristics Sensor : CO 3E 300 7 Range : 300 ppm Remicourt - BE ULoop : 15...30V ILoop : 4...20mA In : 30mA 0H0Cl-10106004-2012 Barcode Serial Nr - Year of production Figure 1 : marking label Description The is a toxic gas and oxygen detector intended for monitoring confined areas in industrial and commercial environment. It is designed to operate in association with a suitable control unit or with a Programmable Logic Controller (PLC) to provide early warnings of toxic gas presence or oxygen deficiency. For further information about the detectable gases or the list of compatible control units, please contact Dalemans. The operates using an electrochemical sensor whose measure is converted by the transmitter into a 4-20 ma electrical signal according to the toxic gas or oxygen concentration. The transmitter deliver the 4-20 ma signal to the control unit or to the Programmable Logic Controller (PLC) through a 2-wire current loop.
3 The main parts of the are : the sensing head; the junction box equipped with a terminal block for electrical connection; the cable gland. Cable gland Junction box Terminal block Sensing head Figure 2 : detector
4 Sensing head The sensing element of the detector is an electrochemical sensor operating according to the amperometry principle. The sensor detects gas by producing a chemical reaction between gas and oxygen contained in the sensor. This reaction produces a small current which is proportional to the gas concentration. That small current is then measured and converted by the 4-20 ma transmitter of the. The sensing head of the consists of : a sensor housing (base + cover); a protective grid; a sensor gasket; an electrochemical sensor; a 4-20 ma transmitter. The sensor housing (base and cover) is a metallic housing wich can be dismantled to allow plug-in sensor replacement. Cover Protective grid Electrochemical sensor Sensor gasket Base 4-20 ma transmitter Figure 3 : sensing head
5 Caution Ensure that local or national regulations relating to the site or the monitored plant are met. The operator must have knowledge of the safety procedure to follow in case of gas alarm. Modification, disassembling and total or partial destruction of the sensing head and its contents, of the cable gland or of the junction box and its contents, may invalidate the essential safety requirements of the whole plant. No additional drilling is allowed on the junction box. The existing openings cannot be enlarged. No additional terminal can be installed on the existing terminal block. The length of the wires of the sensing head may not be modified. Possible defective parts must be replaced by original parts delivered by Dalemans only. The detector must be protected from any risk of mechanical impact. Try to avoid, as much as possible, disconnecting the electrochemical sensor from the 4-20 ma transmitter or storing the detector unpowered for a long period of time. These two situations might affect the sensor performance and life-span. Installation and commissioning Installation and commissioning must be carried out by the manufacturer or his local representative. All the operations described hereafter can be carried out only by specialized personnel who will have been trained beforehand exclusively by Dalemans. Gas detection equipment should be installed as late as possible in any program of construction operations (i.e. construction of a new plant, refitting or maintenance) but before the presence of gas or vapours in the system, so as to avoid damage to sensors resulting in particular from such activities as welding and painting. If already installed, sensors should be protected by an airtight seal to avoid contamination during construction works, and should be clearly marked as being non-operational. Please follow the recommendations hereafter so as to avoid premature ageing of the detector and to guarantee its optimal operation. These recommendations are general directives. Always refer to local regulations/standards in force before proceeding with installation works (i.e. standards IEC 60079-14 and IEC 60079-29-2). Local regulations/standards in force have always precedence on the recommendations of the manufacturer.
6 Location Detectors must be placed so that potential gas accumulations are detected before they create a significant hazard. Inappropriate location of a detector can nullify the effect and the integrity of the gas detection system. The position of the detectors should be determined in consultation with experts having specialist knowledge of gas dispersion, with those who have knowledge of process plant system and equipment involved, and with safety and engineering personnel. Should you require any further guidance or assistance please contact Dalemans. Detectors should be readily accessible to permit regular calibration, maintenance and electrical safety inspection. It must be possible to access and fit all accessories or test equipment needed for these operations on the detector. The location of every detector must be recorded and available to the safety personnel. Points to consider for positionning the gas detectors Hazard level and potential sources of gas release. The combination of sources of gas release with propagation effects. Access for maintenance including calibration and verification. Protection of the system against operational hazards of the plant. Protection of the detector against mechanical impact. Vibration isolation mountings if necessary. The detector should never be positioned directly above or below a water point. For outdoor installation, a protection against rain and/or sun exposition shall be installed. Detector should not be located in air currents, close to air extractors or in ventilation ducts. Always observe the operational temperature range of the sensor (refer to specifications). If target gas is lighter than air (density with respect to air < 1), place the detector at a high level. If target gas is heavier than air (density with respect to air > 1), place the detector at a low level. If target gas has a unit weight close to air unit weight, place detectors at both high and low level. Gas density increases when temperature decreases. Characteristics of some gases Gas Formula Density (air=1) Ammonia NH 3 0.59 Carbon monoxide CO 0.97 Chlorine Cl 2 2.49 Hydrogen sulfide H 2 S 1.19 Nitrogen dioxide NO 2 1.59 Oxygen O 2 1.11 Sulfur dioxide SO 2 2.26
7 94 79 166 94 79 8.0 4.5 45 Figure 4 : mechanical pattern (in mm)
8 Mounting The detector should be mounted flat on a wall and according to the mechanical pattern given on Figure 4. Attach the detector to the wall using suitable screws and plugs (see Figure 4). Install the detector so that the sensing head is never pointing upward. Make sure that dust will not block the sensor and that water will not run into the sensing head. Electrical wiring Wiring must comply with local regulations and standards in force and meet the electrical requirements of the detector. Dalemans recommends the use of a cable with a shielded or screened twisted-wire pair. Observe the following requirements for the wiring of the : Recommended cable : 2 x 0.5 mm² twisted and screened pair. Cable length : maximum 1000 m. Overall cable diameter : maximum 8 mm. The cable shielding or screening must be connected to the ground of the control unit/plc. The cable gland must be sufficiently tightened on the cable to ensure a good sealing The wires end must be stripped over a length of 8 mm. 2 x 0.5 mm² 100 mm Figure 5 : cable stripping
9 Connecting the cable to the terminal block Unscrew the four screws of the junction box and remove the cover to access to the terminal block of the detector. Wires must be stripped and plugged so that the gap between insulation and the metallic edge of the terminal connection does not exceed 1 mm distance. Connect wires according to the diagram given in Figure 6 below. + RED - BLUE Figure 6 : electrical connection
10 Connection to a Dalemans control unit The connection of the detector to a Dalemans control unit requires a 2-wire current loop. The electrical connection must be made with respect to polarity between the and the control unit. For instructions about the electrical connection of the control unit, refer to the instruction manual of the original equipment. + - DALEMANS control unit MIN 10 Vdc Figure 7 : Dalemans control unit Connection to a Programmable Logic Controller (PLC) For instructions about the electrical connection of the PLC, please refer to the original equipment instruction manual. Prior to connecting the to a PLC please read the instructions below regarding the loop resistance. Use an external stabilized power supply for the detector (+24 Vdc). Ensure that the polarity of the output signal meet the polarity of the PLC input. Put a measuring resistor on the PLC input. Choose the resistor value according to the input scale. The resistor must have a power rating of at least 1 Watt. MAX 1000 m + V+ (24 Vdc) 0 V Stabilized power supply MIN 10 Vdc R Measure - Signal 0-5 V PLC 0 V MIN. 1 Watt Figure 8 : Programmable Logic Controller (PLC)
11 Maximum loop resistance for PLC The operating voltage range of the is from 10 up to 30 Vdc. The supply voltage has direct influence on the MAXIMUM loop resistance which includes the cable resistance and the measuring resistor of the PLC. Example : consider a 24 Vdc supply voltage. The minimum operating voltage is 10 Vdc. The allowable voltage drop due to the MAXIMUM loop resistance is 14 Vdc. The MAXIMUM loop resistance is : R Loop = 24-10 = 14 0.02 I MAX With I MAX = maximum loop current (20 ma) = 700 ohms For a 1 to 5 Vdc input scale, the measuring resistor to put on the PLC input will be : R Measure = 5 0.02 = 250 ohms Therefore, the maximum allowable resistance for the cable will be : R Cable = 700-250 = 450 ohms 1000 900 800 700 700 ohms 600 500 400 Operating voltage range 300 200 24 V 100 0 5 10 15 20 25 30 Figure 9 : supply voltge vs R Loop
12 Maintenance Regularly remove dust from the sensing head and the junction box with a wet cloth ONLY so as to limit the risk of electrostatic sparks. PRIOR to operating maintenance, calibration or service works check with a portable apparatus that no gas is present in the atmosphere. Calibration Gas detection equipment must be calibrated at least once a year, in some cases three or four times a year or even more to mitigate the loss of sensitivity of the sensor. This calibration must be performed according to the procedure given by the manufacturer or his local representative, and in any case by qualified personnel who will have been trained by Dalemans. Calibration consists of placing the sensor of the detector in an atmosphere of air and a known concentration of the target gas. It is essential to avoid the calibration atmosphere being influenced by the nature of the ambient air or by draught air. Replacement of the protective grid See Figure 3 for a detailed view of the sensing head. Unscrew the cover of the sensing head and remove it with care. Replace the protective grid and the sensor gasket with new parts. Check that the sensor is still properly positioned on the 4-20 ma transmitter. Perform calibration according to the procedure given by Dalemans or his local representative. Screw up the cover of the sensing head. Replacement of the measuring sensor Prior to replacing the sensor, power off the detector, inhibit the safety function of the detector on the gas detection system and secure any output device connected to the system to prevent unintended actuations and false alarms. Unscrew the cover of the sensing head and remove it with care. Unplug the sensor while holding the 4-20 ma transmitter in place. Place the new sensor on the 4-20 ma transmitter. Power on the detector and perform calibration according to the procedure given by Dalemans or his local representative. Ensure that the protective grid and the sensor gasket are still properly positioned in the cover of the sensing head. Screw up the cover of the sensing head.
13 Troubleshooting Symptom(s) Non-zero reading Non-zero reading when no gas is present Reading value too high or too low Zero reading in presence of gas Possible cause(s) Possible presence of gas. The detector needs to be calibrated. The detector needs to be calibrated. The sensor is blocked by dust. Pollution of the sensor : replace the sensor and perform a full calibration. Wrong or defective wiring. Spare parts Article code Cable gland - M16 (5-8 mm) PRE00000025 Ferrite FER00000001 Gasket for sensor MEC00000018 Instruction manual IMP00000059 Junction box BOI00000199 Protective grid MEC00000017 Screw - M4 x 6 mm VISVIS00042 Screw for cable gland - M16 PRE00000026 Screw for sensing head - M20 PRE00000007 Sensing head Depends on the type of sensor Sensing head cover (brass) MEC00000014 Terminal block - 2p + DIN rail BOR00000092 Transmitter board - 4-20 ma BASTRX00017
14 Specifications MODEL Material Sensing head Brass (CuZn 39 Pb 3 ) or stainless steel 1.4404 (AISI 316L) Junction box Polystyrene Dimensions / Weight 165 x 94 x 57 mm / 540 g Sensor type Electrochemical Output signal 4-20 ma current loop Adjustments Zero and calibration by potentiometers Target gas (1) Density (air = 1) TLV Range Ammonia (NH 3 ) 0.59 20.00 ppm 0-100 ppm 0-1000 ppm 0-5000 ppm Carbon monoxide (CO) 0.97 25.00 ppm 300 ppm 0-500 ppm 0-1000 ppm Nitrogen dioxide (NO 2 ) 1.59 3.00 ppm 0-20 ppm 0-50 ppm Oxygen (O 2 ) 1.11-0 - 25 % Accuracy ± 1.5 % full scale Response time (T90) < 45 s Expected operating life span > 2 years Electrical characteristics 10-30 Vdc / 30 ma Storage temperature -40 C to +80 C Operating conditions Temperature -10 C to +40 C Ambient humidity 20-90 % RH Intermittent humidity 10-99 % RH Pressure 90-110 kpa Cable 2 x 0.5 mm² twisted and shielded pair (max. 1000 m) Wiring 2 wires Loop resistance 50 to 750 ohms Ingress protection (box) IP65 Cable entry 1 x M16 (1) Non-exhaustive list - Other gases upon request.
OFFICIAL DEALER DALEMANS s.a. rue Jules Mélotte 27 B-4350 Remicourt Phone +32 (0)19 54 52 36 Fax +32 (0)19 54 55 34 info@dalemans.com www.dalemans.com