Operation l 4-19
4
Operation
HTC DC Control Alarms
PASSIVE ALARMS
Passive alarms flash the alarm code and display process temperature until the
alarm condition goes away,or it becomes a shutdown alarm.
Code Description Alarm LED
P1 Process Temperature Deviation Blinking Red

SHUTDOWN ALARMS

Shutdown alarms flash the alarm code and display process temperature. The HTC
process air heater should stop when the process temperature is below 150°F
(65.6°C) but should still flash the alarm code until the Acknowledge Alarm button
is pressed. If the alarm condition is still active,the HTC cannot start, it will flash
the alarm code again. If the alarm condition is not active,the display should return
to the normal default screen display and the HTC is ready to run.
Alarms place the control in “standby” mode. After the alarm is corrected and
acknowledged,cycle the heater Standby/Enable switch to “Standby” then back to
“Enable” to r estart the process control.
Code Description Alarm LED
A1 Process High Temperature Solid Red
A2 Process Temperature Loop Break Solid Red
A3 Process Heater Box High Temperature Solid Red
A10 RTD Integrity Solid Red
A39 EEProm Write Error-Internal Control Solid Red
Board Problem
A49 Process Protection High Alarm Solid Red
A50 Process Differential Alarm Solid Red