Technical data

Configuring Messages
16.9 Configuring the 'Reporting of System Errors'
Programming with STEP 7
386 Manual, 05/2010, A5E02789666-01
16.9.6 Generated Error OBs
Depending on the CPU, you can generate the following Error OBs with "Report System Error":
• OB 70 (I/O redundancy error) with a call for the generated diagnostic FB. This OB only exists
with H-CPUs.
• OB 72 (CPU redundancy error) with a call for the generated diagnostic FB. This OB only exists
with H-CPUs.
• OB 73 (communication redundancy error) with a call for the generated diagnostic FB. This OB
only exists with a few H-CPUs.
• OB 80 (time error)
This OB is generated without content to prevent the CPU from going to STOP when a
communication error occurs. Errors are not evaluated, no message is generated.
• OB81 (power supply error) with a call for the generated diagnostic FB.
• OB82 (diagnostic interrupt OB) with a call for the generated diagnostic FB.
• OB83 (plug/remove interrupt) with a call for the generated diagnostic FB.
• OB84 (CPU hardware fault)
This OB is generated without contents so that the CPU does not switch to STOP mode when
communication errors occur (for example, problems with the MPI terminating resistor when
inserting and removing the MPI cable). Errors are not evaluated; no message is generated.
• OB85 (program execution error)
If 'Report system error' creates this OB during the generation of the diagnostic blocks,
additional networks are inserted which realize the following program sequences:
The CPU is prevented from switching to STOP when there is an error updating the process
image (for example, removing the module). This is so that the diagnostic FB in OB83 can be
processed. Any CPU STOP setting after a Report System Error message takes effect in OB83.
With all other OB85 error events, the CPU goes into STOP mode.
If OB 85 already exists, it is not changed by 'Report system error'.
• OB86 (failure of an expansion rack, a DP master system, or a distributed I/O device) with a call
for the generated diagnostic FB.
If the Error OBs Already Exist...
Existing error OBs are not overwritten. If required, the call for the diagnostics FB is appended.
If the Configuration Includes Distributed I/O Devices...
For evaluating errors in distributed I/O, the generated FB calls SFC13 automatically (reads
diagnostic data of the DP slaves). To ensure this function, the generated FB must be called either
only in OB1 or in a cyclic interrupt OB with a short time cycle and in startup OBs.