User Manual

10
Typical connection to the Macurco DVP-120 Detection and Ventilation Control Panel
Power Up
The TX-12-ND steps through an internal self-test cycle for the first 1 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 and
the gas type, then count down from 60 to 0 (if the display option 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 TX-12-ND will show the current concentration of NO2 ppm or “0.0” (zero) in clean air.
When the NO2 concentration reaches the Fan Relay setting (1.0ppm, for example) the display will flash back and forth between
“FAn” and “1.0”. 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 NO2 concentration reaching the Alarm Relay setting, (5.0ppm, for example) the
display will flash back and forth between “ALr” and “5.0”. The buzzer will sound indicating “Alarm” if the buzzer is turned “On”.
With the display function turned off the display does not show the NO2 concentration, but will show “ALr” when the Alarm relay
is activated.
3. With the 4-20 mA function turned “On” and the NO2 concentration climbing the 4-20 mA signal will ramp up corresponding to
the concentration (0-20 ppm).