GDC-350 Operation Manual
5909-9000 Rev 1
29
NOTE:
When calibrating solid-state sensors for combustibles or
refrigerants, the span gas must be humidified. The use of a
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 through the chamber, it absorbs water
which acts to humidify it and the humidified span gas flows over the
sensor. (See table on page 34 for ordering information.)
5.4. Calibrating the On-Board Sensor
SETTING SPAN GAS VALUE
Step
Setting Span Gas Value Procedure
1
Move the jumper on J6 to P2 and move the jumper on J7 to P2.
2
The audible alarm beeps once for confirmation. The system is now
waiting for the user to set the desired span value.
3
Attach the volt meter leads to test points TP1 and TP2.
4
Using the UP or DOWN push-buttons, achieve the calculated voltage on
the volt meter.
5
Move the jumpers from J6 and J7 back to their P1 resting positions.
CALIBRATING THE NULL (ZERO)
Step
Calibrating the Null (Zero) Procedure
1
Attach a regulator to a cylinder of zero air (or nitrogen).
2
Insert the calibration adapter into the sensor opening on the front of the
enclosure. 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.
3
Open the regulator valve fully allowing zero air to flow over the sensor.
4
Move the jumper on J6 to P2 and move the jumper on J7
to P3. The
audible alarm beeps once for confirmation. The system is now starting
the zero calibration stabilization time (30 seconds).
5
If desired, attach the volt meter leads to test points TP1 and TP2. The
reading should be 0.0 VDC.
6
The instrument will beep twice when the calibration begins. Leave the
zero air flowing over the sensor until the GDC-350 beeps three times
indicating the procedure is finished (1 minute).
7
Move the jumpers from J6 and J7 back to their P1 resting positions and
remove the zero air (or nitrogen).
