S5-115F Manual
Rules Governing the Use of the S5-115F
10.17.3 Operating System and User Program Response in the Case of I/O ETV*3
and 4
While I/O ETVs 1 and 2 end the error response with PLC STOP or passivation of I/Os, you receive
only the relevant error message when you select
•
I/O ETV 3 with signal group 28 and
•
I/O ETV 4 with signal group 27 or 28.
The error response is left to the user program. It evaluates the error messages and initiates all
safety responses, such as safe shutdown.
•
Error analysis
Error analysis is carried out in the same way as for I/O ETVs 1 and 2. Analysis is continued after
an I/O error is discovered until the error is corrected. This results in the PLC cycle being loaded
with the discrepancy time because of cyclic comparison.
•
Error message
Every error detected with a different address is entered in the error stack of the error DB.
If a SINEC L1 LAN is available, the error DB body is transferred to the SINEC L1 master.
The error is sent to the CP 523, provided one has been configured as a message module for
printing COM 115F error messages.
Up to 16 errors are entered in the error stack. The 17th error message results in PLC STOP due
to the central safety significance in the case of I/O ETV 3 and 4.
•
Standard value generation
The standard value is generated
- After error detection in cyclic image comparison
In the case of I/O ETV 4 with signal group 27, the standard value is generated by
- ANDing the nomatching DI or R DI signals
In the case of I/O ETV 3 or 4 with signal group 28 the standard value is generaterated by
- ORing the nonmatching DI or RB DI signals
- In the case of discrepancy when accessing a non-interrupt DI direct, it can be the case that
the value cannot be read since a test is taking place. In such a case, the nonmatching DI bits
are read from the DI byte stored before the test.
- No standard value is generated in the case of an AI comparison error. The passivation value
configured in FB 250 is used here (as in the case of I/O ETV 2).
* I/O ETV = I/O Error Tolerance Variant
EWA 4NEB 811 6148-02
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