Siemens SIMATIC S7 F Manual page 247

Fail-Safe Blocks
Name
Outputs: CHADDR00
...
CHADDR07
DIAG_1
DIAG_2
PROFIsafe1
PROFIsafe2
SM1, SM2 – redundant modules
Error Information at the Output DIAG_1/2
DIAG_1
Byte 0
Bit 0: TIMEOUT error on SM1
Bit 1: Common error on SM1
Bit 2: CRC value/watchdog error on SM1
Bit 3: Reserved
Bit 4: TIMEOUT error on CPU
Bit 5: Watchdog error on CPU
Bit 6: Check value error (CRC) on CPU
Bit 7: Reserved
Byte 1
Bit 0: Discrepancy error on channel 0 of SM1
...
Bit 7: Discrepancy error on channel 7 of SM1
Byte 2
Reserved
Byte 3
Reserved
Note
In byte 0 of DIAG_1/2, the most recent error information remains stored until a new
error occurs, even if the error has already been eliminated.
Fail-Safe Systems
A5E00085588-03
Data Type Explanation
F_WORD Interconnection with the F
channel driver of channel 0
F_WORD Interconnection with the F
channel driver of channel 7
DWORD Diagnostic information for
SM1, see table below
DWORD Diagnostic information for
SM2, see table below
F_BOOL Identify failure on a specific
PROFIsafe bus
F_BOOL Identify failure on a specfic
PROFIsafe bus
DIAG_2
Byte 0
Bit 0: TIMEOUT error on SM2
Bit 1: Common error on SM2
Bit 2: CRC value/watchdog error on SM2
Bit 3: Reserved
Bit 4: TIMEOUT error on CPU
Bit 5: Watchdog error on CPU
Bit 6: Check value error (CRC) on CPU
Bit 7: Reserved
Byte 1
Bit 0: Discrepancy error on channel 0 of SM2
...
Bit 7: Discrepancy error on channel 7 of SM2
Byte 2
Reserved
Byte 3
Reserved
Default
Interconnected
automatically
Interconnected
automatically
0
0
0
0
8-59