Rockwell Automation 900-TC32 Digital Temperature Controllers, Series B - Manual (Page 145)

Publication 900-UM007D-EN-E - January 2011
Parameter Adjustments & Application Considerations 4-9
Alarm Latch
Alarm latch is a function where you can configure the alarm output once
turned ON to stay ON regardless of the process temperature.
The alarm latch function can be canceled by:
1. Turning the controller power OFF. Note, however, that it can also be
canceled by switching to the Initial Setting function group,
Communications Setting function group, Advanced Setting function
group, or Calibration function group.
2. Use the PF key (900-TC8).
3. Use an event input (900-TC8 and 900-TC16).
Summary of Alarm
Operations The following figure summarizes the operation of alarms when the Alarm
Type parameter is set to “lower-limit alarm with standby sequence” and “close
in alarm” is set.
Figure 4.16 — Operation of Alarms Summary
Table 4.A
Symbol Parameter: Group Description
alh✽
Alarm 1 to 3 Hysteresis:
Initial Setting function
group Alarm
rest
Standby Sequence:
Advanced Setting
function group Alarm
✽ = 1 to 3
OFF
ON
PV
Alarm type: Lower-limit alarm with standby sequence
Alarm value
Alarm hysteresis
Time
Standby sequence
canceled
Alarm
Output OFF (open)
ON (closed)