WAGO 750 Manual page 69

WAGO I/O System 750
753-661/000-004 4FDI 24V PROFIsafe
If the process image of the F I/O module transfers a 0-signal due to the input
signal states, and a deviation of the input signal states from the valence rule is
then detected, discrepancy time monitoring starts. Discrepancy time monitoring is
not terminated until a 0-signal or 1-signal is detected.
While discrepancy time monitoring progresses in the F I/O module, the "0" value
is output from the channel pair in question to the safe PLC as a safe process
value.
Behavior of the F I/O Module after the Discrepancy Time Elapses
If the invalid input signal status is detected by the F I/O module for longer than
the discrepancy time setting, a discrepancy error occurs. The channel pair is
passivated, and the diagnostic message "Discrepancy time exceeded" is output.
The discrepancy error can be caused, for example, by a wire break in a signal
line, a sensor error etc.
Behavior of the F I/O module in the event of discrepancy errors
If the F I/O module detects a discrepancy error, the channel pair is passivated by
the process values and by the channel statuses of the corresponding digital
inputs being set in the process image to the value "0." You can acknowledge the
reported error(s) after the cause of the error has been eliminated (see section
"Commissioning" > ... > "Restart Inhibit Ix and Ix+1 Parameter").
Version 1.0.0, valid from HW/SW Version 01/01
Commissioning 69
Manual