User Manual

10
Typical connection to the Macurco DVP-120 Detection and Ventilation Control Panel
Power Up
The GD-12 cycles through an internal self-test cycle for the first minute that it is powered. The unit will execute the test cycle any time
power is dropped and reapplied (i.e. power failure). During the self-test cycle the unit will display the firmware version number, then
count down from 60 to 0 (if the display setting is “On”) and finally go into normal operation. The alarm relay will be activated for 10
seconds and the fan relay for 60 seconds during the power-up cycle unless the “Power Up Test” (PUt) option is OFF. The indicator light
(LED) will flash green during the self-test cycle. At the end of the 1 minute cycle, the unit will take its first sample of the air and the
indicator light will turn solid green.
Operation
1. With the display function turned “On”, the GD-12 will show the current concentration of gas % LEL or “0” (zero) in clean air.
When the gas concentration reaches the Fan Relay setting (10% LEL, for example) the display will flash back and forth
between “FAn” and “10”. With the display function turned ”Off”, the display does not show the gas concentration, but will show
“FAn” as long as the fan relay is activated.
2. With the display function turned “On” and the gas concentration reaching the alarm relay setting, (20% LEL, for example) the
display will flash back and forth between “ALr” and “20”. The buzzer will sound indicating “Alarm” if the buzzer is turned “On”.
With the display function turned off the display does not show the gas concentration, but will show “ALr” when the Alarm relay
is activated.
3. With the 4-20 mA function turned “On”, the 4-20 mA output will correspond to the concentration (0-50% LEL). The display will
show “FAn” and “ALr” and sound as outlined above.