Rockwell Automation 900-TC32 Digital Temperature Controllers, Series B - Manual (Page 116)

Publication 900-UM007D-EN-E - January 2011
3-46 Configuration & Basic Operation
Precaution
If a shorter PV rate of change calculation period is configured, outputs for the
PV change rate alarm may repeatedly turn ON and OFF for a short period of
time. Therefore, it is recommended that the PV change rate alarm be used with
the alarm latch turned ON.
Figure 3.92
Heater Burnout Alarm
(HBA), Heater Short Alarm
(HSA), and Heater
Overcurrent Alarm (HOA) HBA, HSA, and HOA Alarm Detection — 900-TC8 & 900-TC16 only
Heater burnout and heater overcurrent detection are executed by:
1. measuring heater current with an optional current transformer (single
phase) or
2. transformers (3 -phase) while the control output for heating is ON, and
HS detection is executed by measuring heater current while it is OFF.
For details, refer to the following table and figure below..
Note: Heater burnout, heater short, and heater overcurrent detection cannot
be used with the control output for cooling.)
PV
Alarm value
Time
PV change width for PV rate
of change calculation period
Alarm function
OFF
ON
OFF
ON
0
Table 3.O
Parameter Name
Configurable
Range
Units Default
PV Rate of Change Calculation Period 1...999 Sampling Cycle 4 (1 s)