User manual

Publication 1756-RM093F-EN-P - January 2010 73
Monitor Status and Handle Faults Chapter 7
Output Fault Latch and Reset Flowchart
Ladder Logic Example 3
Start
Does this safety function require
operator intervention after a safety
output failure?
Write logic to latch output
failure. (Example Rung 0)
Is output fault information required
for diagnostic purposes?
No
Yes
Yes
No
Write logic to set outputs to a
safety state. (Example Rung 2)
Write logic to unlatch output
failure (Example Rung 1)
Write logic to latch output
failure. (Example Rung 0)
Done
0
/
/
Node30:I.OutputStatus
L
Node30OutputsFaulted
1
FaultReset
ONS
InputFaultResetOneShot
Node30:I.OutputStatus
U
Node30OutputsFaulted
2
Node30OutputsFaulted
RedundantOutputTag.O1
Node30:O.Pt00Data
Node30:O.Pt01Data
RedundantOutputTag.O2
Node 30 is an 8-point input/8-point output combination module.
If the output status is not OK, then latch the output faulted indication.
If the raising edge of the fault reset signal is detected and the input status is OK, then unlatch the inputs faulted indication.