Watlow CLS200 - Manual (Page 181)

CLS200 Series User’s Guide Chapter 9:Troubleshooting and Reconfiguring
Doc.# 0600-3050-2000 Watlow Anafaze 165
Responding to Process and Deviation Alarms
In a heating application, a low process or low deviation
alarm may indicate one of the following:
• The heater has not had time to raise the temperature.
• The load has increased and the temperature has fall-
en.
• The control status is set to manual instead of automatic.
• The heaters are not working due to a hardware failure.
• The sensor is not placed correctly and is not measuring
the load’s temperature.
• The deviation limit is too narrow.
• The system is so poorly tuned that the temperature is
cycling about setpoint by more than the alarm limit.
NOTE! In cooling applications, similar issues cause
high process and high deviation alarms.
In a heating application, a high process alarm or high devi-
ation alarm may indicate one of the following:
• The setpoint and high process limit have been lowered
and the system has not had time to cool to within the
new alarm limit.
• The control status is set to manual and the heat out-
put is greater than 0%.
• The load has decreased such that the temperature has
risen.
• The heater is full-on due to a hardware failure.
• The system is so poorly tuned that the temperature is
cycling about setpoint by more than the alarm limit.
Resetting a Process or Deviation Alarm
Your response to an alarm depends upon the alarm type
setting, as explained in Table 9.2 below.
Table 9.2 Operator Response to Alarms
Alarm
Type
Operator Response
Control
The operator does not need to do anything.
The alarm clears automatically when the pro-
cess variable returns within limits.
Alarm
Acknowledge the alarm by pressing ALARM
ACK on the controller or by using software.
The alarm clears after the process variable
returns within the limits and the operator has
acknowledged it.