Rockwell Automation 1797-OE8 FLEX Ex Analog Modules User Manual - Manual (Page 15)

Publication 1797-6.5.1 - May 2005
About the FLEX Ex Analog Modules 1-5
Remote Fault Alarm
The Remote Fault Alarm is primarily intended for use with remote transmitter
loops.
For example, the remote transmitter may be measuring temperature and
converting it to a standard mA signal. In such a loop, though, the input module
cannot determine the state of the loop on the far side of the transmitter.
However, the remote transmitter may be capable of diagnosing a problem in
the remote loop and signal the input module local loop with a preprogrammed
out of range (high or low) value.
The Remote Fault Alarm allows the 1797-IE8 and -IE8NF modules to work
with transmitters like the one just described. You must use the Remote
Transmitter Error Up or Down feature, see page 2-3, to configure your
application for Remote Fault notification.
For example, you must determine if you want a remote fault to cause
high out of range values or low out of range values to be returned to
the controller.
Using Remote Fault Alarm to Determine High High or Low Low Alarm Levels
If you do not have a remote transmitter in your loop, this alarm can also be
used to program a high high or low low alarm level between the levels which
actuate the overrange or underrange alarms and the high or low local fault
alarms.
IMPORTANT
Once the alarm is issued, it remains active as long as the
input signal value remains above the programmed value.
IMPORTANT
When establishing high high or low low alarms, you can
only select one side (high or low). You must use the
Remote Transmitter Error Up or Down feature in
conjunction with this alarm.