User Manual

10
Typical connection to the Macurco DVP-120 Detection and ventilation Control Panel
Power Up
The CM-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 CM-12 will show the current concentration of CO ppm or “0” (zero) in clean air. When
the CO concentration reaches the Fan Relay setting (35 ppm, for example) the display will flash back and forth between “FAn”
and “35”. With the display function turned ”Off”, the display does not show the CO concentration, but will show “FAn” as long as
the fan relay is activated.
2. With the display function turned “On” and the CO concentration reaching the Alarm Relay setting, (200 ppm, for example) the
display will flash back and forth between “ALr” and “200”. The buzzer will sound indicating “Alarm” if the buzzer is turned “On”.
With the display function turned off the display does not show the CO concentration, but will show “ALr” when the Alarm relay is
activated.
3. With the 4-20 mA function turned “On” and the CO concentration climbing, the 4-20 mA signal will ramp up corresponding to
the concentration (0-200 ppm, for example). The display will show “FAn” and “ALr” and sound as outlined above.