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Rockwell Automation Publication 1734-UM013C-EN-P - August 2010
Chapter 2
Safety Functions
I/O Status Data
In addition to I/O data, the module provides status data for monitoring the I/O
circuits. The status includes the following data, which can be read by the
controllers. Note that 1 = ON/Normal and 0 = OFF/Fault/Alarm:
•
Individual Point Input Status
•
Combined Input Status
•
Individual Point Output Status
•
Combined Output Status
•
Individual Test Output Status
•
Individual Output Monitor (actual ON/OFF state of the outputs)
Individual Point status indicates whether each safety input, safety output, or test
output is normal (normal status: ON, faulted status: OFF). For fatal errors,
communication connections may be broken, so the status data cannot be read.
Status bits are OFF in the controller data table when the connection is lost.
Combined status is provided by an AND of the status of all safety inputs or all
safety outputs. When all inputs or outputs are normal the respective combined
status is ON. When one or more of them has an error, the respective combined
status is OFF. This is known as the combined safety input status or combined-
safety output status.