User Manual

Publication 1746-UM010B-EN-P - April 2001
3-8 Configuring the Module
Alarm Dead Band
Word 15 for Channel 1
Once the temperature alarm bits are on, they remain on until the
temperature drops below the high alarm by the alarm dead–band
value or rises above the low alarm by this value.
The alarm dead band applies to the CV value at the high and low
temperature alarms and deviation alarm values and provides a
hysteresis effect. Low and high alarms are defined as:
• Low Alarm With Dead Band — When the temperature falls
below the user–defined low alarm value, the low alarm bit is
turned on. When the temperature rises above the level of the
low alarm value but still below the level of the dead–band
value, the low alarm bit remains on. Only when the temperature
rises above the dead–band level will the alarm bit be turned off.
• High Alarm With Dead Band — When the temperature rises
above the user–defined high alarm value, the high alarm bit is
turned on. When the temperature falls below the level of the
high alarm value but still above the level of the dead–band
value, the high alarm bit remains on. Only when the
temperature falls below the dead–band level will the alarm bit
be turned off.
Deadband
Deadband
Temperature
Time
alarm off
alarm on
high (CV)
alarm level
low (CV)
alarm level