Hi,

I not able to resolve an issue I have on an S7 CPU 1516F-3 PN/DP (V2.1).

I modified something in an F-block (modification of the name of a tag, that's all), compiled the software (only difference) and then downloaded it online but got an error about CRCs.

Now I cannot start the PLC anymore (an F-system block if stopping the CPU each time I try to start it).

I have no error when compiling on the ES but as soon as I tried to download in the PLC, it gives me an error about CRCs of collective F-signature online/offline that don't match.

I tried to compare online/offline and it shows me one difference in an F-block (system) but when I tried to download the F-block it refuses because it doesn't see any difference.

Anyone has an idea on how to solve that? Please help :(

I don't know if at this point, I should factory reset the PLC or ...

How should I proceed?

I already did a Compile > Software (rebuild all blocks) by right-clicking the PLC Blocks on the left pane. It didn't solve the problem.

Is there an other way to compile Safety block?

Thank you

If anyone is looking for an answer, here is what I did to resolve my issue:

- In the safety administration, on the runtime group, change OB123 by OB124.

- In hardware configuration, change any fail-safe parameter (monitoring time for instance)

- Compile > Hardware (rebuild all)

- Compile > Software (rebuild all)

- Go offline or make sure you're offline

- Download to device > Hardware and software

I guess it needs to have a change in order to compile and download everything back to the device.

MatLcq

I guess it needs to have a change in order to compile and download everything back to the device.

No, it doesn't need to change the actual block numbers, only to compile the safety program so that it generates the CRC again. Then download.

You can try to force a 'full' download with Online -> Download and reset PLC program

help

Downloads all blocks, including blocks that were not changed and resets all values to their initial state. Retentive values are also reset. 

Best regards,
yy1

I did some changes in IO unit, in my 2nd Profinet IO extension I inserted additional Analog card, then configured in TIA portal the right update, but unfortunately I ran into same issue & did the following things & none of them worked:

# rebuild both complete Hardware & Software

# check of any hardware inconsistency & as a while ago my hardware settings were right so nothing wrong there. 

# took help from other suggestions from this thread, none worked.

Which worked for me is:

# Put PLC in run mode.(STOP mode might work as well, i don't know)

# Formatted complete Memory Disk of the main PLC (CPU 1511F-1 PN)

# Re-install all Hardware & Software again.

This solved the issue. 

jml_69_69

I did some changes in IO unit, in my 2nd Profinet IO extension I inserted additional Analog card, then configured in TIA portal the right update, but unfortunately I ran into same issue & did the following things & none of them worked:

# rebuild both complete Hardware & Software

# check of any hardware inconsistency & as a while ago my hardware settings were right so nothing wrong there. 

# took help from other suggestions from this thread, none worked.

Which worked for me is:

# Put PLC in run mode.(STOP mode might work as well, i don't know)

# Formatted complete Memory Disk of the main PLC (CPU 1511F-1 PN)

# Re-install all Hardware & Software again.

This solved the issue. 

It helped when I have deleted files in Windows (USB reader).
Jan