Ac Zero Crossing Loss; Over Temp Trial Test Fail - ABB PGC2000 Operation And Service Manual

Any one of the following alarm messages or conditions could be present:
On Background Screen
On Manual Temperature
Control Mode Screen
On Alarm Screen
Cause: Micros #1 and #2 disagree by more than 30 deg C. Micro #1 monitors and controls the
temperature control board. Micro #2 monitors for over-temperature conditions. The measurement of
the two sensors must agree in order to ensure proper over-temp protection.
Perform Test Procedure 30 (Checking Temperature Table Values), Test Procedure 21 (Open
Temperature Sensor), Test Procedure 22 (Shorted Temperature Sensor), Test Procedure 25 (Zone
Input Sensor Open), and Test Procedure 26 (Open or Shorted Heater), as applicable.

AC Zero Crossing Loss

Symptom: Alarm Condition.
Any one of the following alarm messages or conditions could be present:
On Background Screen
On Manual Temperature
Control Mode Screen
On Alarm Screen
The heater output board monitors the AC input with a comparator circuit. This determines the zero
crossover point, which occurs when the magnitude of the AC signal is zero. This point occurs in both
the positive and negative directions. The crossover point is used to coordinate application of power
from the triac to the heating element. Power is applied as the zero crossover point occurs preventing
unnecessary loading and surging on the temperature output circuitry.
It is the customer's responsibility to ensure that the area is safe and and hazard-
free, and will remain so the entire time the analyzer is open. This responsibility
includes ensuring adequate ventilation in analyzer shelter and obtaining proper
work permits, etc.
See "AIR PURGING" in Section 4 for the override function. Do not perform
override until you have read Section 4 completely and you understand and can
perform the procedure requirements.
Remedy: Replace Heater Output Control board.

Over Temp Trial Test Fail

Symptom: Alarm Condition.
2000-OSM, F1
***ALARM:*** (flashing)
Zone (#) (flashing)
*Temp Bd Alarm* (flashing)
Temperature Board:
*Zone Specific
*** TEMP ZONE (#) Alarm ***
*Reasonableness Test
***ALARM:*** (flashing)
*Temp Bd Alarm* (flashing)
Temperature Board:
*No Zero Crossing
CAUTION
6-17