Rockwell Automation 1746-NO8V SLC 500 8-Point Analog Output Module/ User Manual - Manual (Page 35)

Publication 1746-UM026A-EN-P - September 2003
Configuring the Module 4-11
Fault conditions are listed below:
•
CPU Fault
•
Rack power goes away while the external 24V power remains
•
CPU goes out of run mode
•
The modules chassis slot is disabled
Latch Alarms (configuration bit 14)
This setting allows certain alarms to remain latched. This can be useful
if alarm conditions need to be acknowledged by an operator.
Over/Under Limit, Over/Under Range Output at low/high Clamp
Alarm, Open Current Loop and 24v Power Failure alarms are latched
when this feature is enabled. Channel Configuration Error, Fatal
Channel Error and Module/SLC Resetting alarms are not latched and
unaffected by this feature setting.
When the Latch Alarms configuration bit is cleared for a channel, then
the alarm bit allows the alarm condition. If the alarm condition occurs,
then the alarm bit is set. If the alarm condition goes away, then the
alarms bit is cleared.
Reset Latched Alarms (configuration bit 15)
When the Latched Alarms configuration bit is set for a channel and if
the alarm condition occurs and goes away, the bit stays set. Only if
the alarm condition is gone and the Reset Latched Alarms
configuration bit is set will the alarm bit be cleared. If the alarm
condition exists and the Reset Latched Alarms configuration bit is set,
the alarm bit stays set.
TIP
When the rack power is restored, the channel
outputs will go to the reset power state during
power-up self test. After this, the channels will
output their commanded values if enabled with a
valid configuration.
TIP
In Class 1 operation the output will hold the
current value when the module’s chassis slot is
disabled.
TIP
The set and clear parameter feature bits (Bits 7 and 8
of the channel configuration word) must be zero for
the latched alarms to operate.