Specifications

GDC-350 Operation Manual

5909-9000 Rev 3 29

NOTE: When calibrating solid state refrigerant or catalytic sensors, it is

recommended that the span gas 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 (on-board sensor)

Step Setting Span Gas Value Procedure

1 Move the jumper on J6 to P2 and move the jumper on J7 to P2.

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.

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) (on-board sensor)

Step Calibrating the Null (Zero) Procedure

1 Attach a regulator to a cylinder of zero air (or nitrogen).

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.

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).

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).

Move the jumpers from J6 and J7 back to their P1 resting positions and

remove the zero air (or nitrogen).