User manual

Publication 1797-6.5.1 - April 1999
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 module to work with
transmitters like the one just described. You must use the Remote
Transmitter Error Up or Down feature, see page 2-2, 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.
Important:Once the alarm is issued, it remains active as long as the input
signal value remains above the programmed value.
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: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.