Critical Environment Technologies GEM-II, Руководство по эксплуатации

Страница: 49 / 60

© 2014 All rights reserved. Data subject to change without notice. 49
Rev. E | 2014.10 GEM-II - Operation Manual
CALIBRATION SPAN GAS VALUE / 50% OF RANGE SENSOR RANGE
= % OF RANGE
e.g. 100 ppm / 200 ppm = 50% of 4.0 VDC = 2.0 VDC
Therefore the required voltage setting to calibrate with 100 ppm is 2.0 VDC.
NOTE
: When calibrating solid-state sensors for combustibles or refrigerants, the span gas
must be humidified. The use of a CETCI humidification chamber is required. The humidification
chamber sits in line between the cylinder of span gas and the calibration adapter. Remove the
sponge inside the chamber and wet it under the tap. Squeeze out the excess water so it is not
dripping wet and place it back inside the chamber. As gas flows over through the chamber, it
absorbs water which acts to humidify it and the humidified span gas flows over the sensor.
8.4 Calibrating the Internal sensor
8.4.1 Setting Span Gas Value (internal sensor)
Step 1:
Move jumper on J6 to position-2 and move jumper on J7 to position-2. The audible alarm beeps
once for confirmation. The system is now waiting for the user to set the desired value.
Step 2:
Attach digital multi-meter leads to test points TP-1 and TP-2.
Step 3:
Using the UP or DOWN push-buttons, achieve the calculated voltage on the digital multi-meter.
Reference Section
8.3 Calibration Procedure .
Step 4:
Move jumpers from J6 & J7 back to their respective resting positions.
8.4.2 Calibrating the Null (Zero) Value (internal sensor)
Step 1:
Attach regulator to cylinder of zero air, insert calibration adapter into the sensor opening in the
front of the enclosure door, and open regulator valve fully allowing zero air to flow over sensor.
Use a slight twisting motion as you gently push the calibration adapter into the sensor opening.
If the calibration adapter is hard to insert, moisten the O-ring seal slightly then try re-inserting
it.