INSTALLATION Siting of the equipment should be chosen with regard to the following points. a. Away from sources of heat with room for adequate air circulation. b. Within easy reach for operating and maintenance personnel. c. Connecting cables to be electrically shielded ie: M.I.C.C., steel wire armoured, screened cable or steel conduit. Note: Sensor cables should not be run in the same ducting as power cables. SET UP 1. Having powered up allow 5 minutes for the sensor to stabilise. 2. SAFE AREA SENSOR BOARD - the sensor current/voltage should be set by connecting a voltmeter (mV meter reading = mA sensor current) CAUTION - DO NOT EXCEED 360mV (mA). EExd SENSOR BOARD - measuring across sensor terminals W and P adjust the sensor voltage potentiometer for required voltage. 3. Zero the card in clean air by adjustment of the potentiometer marked zero until the GREEN ON/Z LED just turns from GREEN/RED to GREEN. (At this point the output will = 4ma). If you require to check this, connect a digital meter (mV range) to the test pins marked TP1 and TP2, if adjustment is required adjust the 4ma potentiometer (4mV = 4mA).

CALIBRATION With the digital meter connected to the test pins TP1 and TP2 and a reading of (4mV clean air) apply test gas and wait until a maximum reading is obtained, if necessary adjust 20mA potentiometer for the required mV reading for the calibration gas being used. Where 4 to 20mA span = 0 - 100% L.E.L. (Lower explosive level) and the sensor is to be calibrated for Methane which has an L.E.L. of 5% vol, when using 1% Methane in air test gas (20% L.E.L.) a reading of 7.2mc (7.2mA) would be required. Where a digital panel meter is fitted readings should be taken directly from the readout and if necessary adjusted using the 4 and 20mA potentiometers. ADDITIONAL RELAY BOARD ALARM TRIP POINT ADJUSTMENT This level will normally be set at 20% of the range reading i.e. 7.2mA. 1. Connect the DVM as above, using the zero potentiometer adjust for the required trip level (mv). 2. Adjust the alarm level potentiometer until the relay just changes state. 3. Using the zero potentiometer re-adjust the DVM to 4mV. The above adjustment may be carried out in house by connectiong the CV transmitter directly to a DC power supply.

GDS Technologies Ltd
Fusion Point, Ash Lane, Garforth,
Leeds UK LS25 2GA
Tel +44 (0)113 286 0166
Fax +44 (0)113 287 8178
Email sales@gds-technologies.co.uk
www.gds-technologies.co.uk