Specifications

M GD-100 M anual

42 6109-9000 Rev 3

First disable the 3-minute alarm delay on a one-al arm system by moving

the jumper link at JP1 to the off position. Two adjustments are required

and they are both performed on the controller unit.

The alarm threshold volt age (A TV ) is the voltage at which the alarm and

relay activat e at a given gas concentration. This voltage is normally set

3.0V.

Step Adjusting the Alarm Threshold Voltage (ATV)

This voltage (measured on the CAL header) is set using:

• 1 or 2 channel system controllers - the threshol d pot “P3”

• 4 or 6 channel system controllers - the threshold pot “P7”

If the sensor standby voltage (SSV) is great er than the alarm threshold

voltage, as in when a gas leak occurs, then an alarm condition occurs

(red LED, siren, relay operates).

If the SSV falls below 0.18 V, a fault condition will be shown on the

controller (red LE D, no siren, relay does not operate).

Step Adjusting the Sensor Standby Voltage (SSV)

Connect a voltmeter between Pins 4 (-Ve) & 2 (+Ve) of the

sensor terminal connector block for each channel in turn

(CN1, CN2, etc.).

Apply calibration gas of the desired concent ration to the

sensor and wait until the sensor output signal stabilizes, then

adjust the pot that corresponds to the channel being

calibrated.

This should be adjusted until the sensor goes into alarm and

the red LED turns on. (Setup alarm voltage to 0.05V above

the alarm setting.)

Remove the calibration gas and allow the sensor to return to

its standby voltage.

Record this voltage reading and keep on record for

subsequent electrical set-ups. This is now calibrated for the

gas concentration us ed. Repeat for any subsequent

channels.

6 Finally, return jumper JP1 to its pre-calibrated position.