Rockwell Automation 1769-IF4FXOF2F Compact Combination Fast Analog I/O Module - Manual (Page 48)

48 Publication 1769-UM019A-EN-P - October 2008
Chapter 3 Module Data, Status, and Channel Configuration
Process Alarms
Process alarms alert you when the module has exceeded configured
high or low limits for each input channel. You can latch process
alarms. Process alarms can generate interrupts.
(1)
A channel’s process
alarms are set at two user-configurable alarm trigger points.
•
Process Alarm High
•
Process Alarm Low
The operation of each input channel’s process alarms are controlled
by bits in the Configuration Data file. Enable alarms for a channel by
setting (EA = 1) the EA bit for that channel. Set the AL bit (AL = 1) for
a channel to enable alarm latching. Set the EI bit (EI = 1) for a channel
to enable interrupts on that channel’s process alarms.
(1)
Each channel’s process alarm-high data value and process alarm-low
data value are set by entering values in the corresponding words of
the Configuration Data file for that channel.
The values entered for a channel’s process alarms must be within the
full-scale data range as set by the Input Data Format selected for that
channel. If the process alarm data value entered is outside the
full-scale data range set for a channel, the module indicates a
configuration error.
Alarm Deadband
You may configure an alarm deadband to work with the process
alarms. The deadband lets the process alarm status bit remain set,
despite the alarm condition disappearing, as long as the input data
remains within the deadband of the process alarm.
This illustration shows an example of input data that sets each of the
two alarms at some point during module operation. In this example,
latching is disabled; therefore, each alarm turns OFF when the
condition that caused it to set ceases to exist and the input data clears
the alarm deadband regions.
(1) Module interrupts are not supported by all bus masters. Refer to your controller’s user manual to determine
whether it can support module interrupts.