RKI Instruments GD-K8A - Manual (Page 11)

Model GD-K8A Diffusion Detector Head • 7
5. Connect the ground bolt to a locally available earth ground.
6. Connect the cable shield’s drain wire to an available earth (chassis) ground at the
controller. The grounding screw on each controller conduit hub is an example of an
earth (chassis) ground.
Start Up
This section describes procedures to start up the GD-K8A and place it into normal
operation.
Introducing Incoming Power
1. Complete the installation procedures described earlier in this manual.
2. Verify that the power wiring to the controller is correct and secure. Refer to the
controller instruction manual.
3. Turn on or plug in the incoming power to the controller.
4. Turn on the controller.
5. Verify that the controller is on and operating properly. Refer to the controller
instruction manual.
CAUTION: Allow the GD-K8A to warm-up for at least 1 hour before you continue with the next
section. If the batteries in the ASK are dead and the GD-K8A has been off power for
an extended period of time, allow the GD-K8A to warm up overnight.
Setting the Zero Signal
CAUTION: If you suspect the presence of toxic gas in the monitoring environment, use the
calibration kit and the zero air calibration cylinder to introduce “fresh air” to the
sensor and verify an accurate zero setting.
1. Verify that the GD-K8A is in a fresh air environment (environment known to be free of
toxic and combustible gas and of normal oxygen content, 20.9%).)
2. Release that snap latch on the right side of the housing that secures the door and open
the door.
3. Use small test clips to connect a milliampmeter to the output check pins on the
amplifier.
4. Verify a reading of 4.0 mA on the milliampmeter. If necessary, use the zero pot to
adjust the milliampmeter reading to 4.0 mA.
CAUTION: Do not adjust the span pot at this time unless a full calibration is performed. The
GD-K8A is factory calibrated before shipment. If a calibration is performed at start
up, allow at least two hours for warm-up.
5. Remove the milliampmeter test clips.
6. Close the door and secure it with the snap latch.
7. The GD-K8A will now monitor the ambient air and send the target gas reading to the
controller via a 4 - 20 mA signal.