Siemens CPU error

Good day guys,

im battling abit with an error on a Siemens CPU, im more a rockwell guy so forgive my ignorance.

I randonmly get pop up errors on the cpu and i cycle power and it goes away but happens shortly afterwards again.

We have changed batteries and power supply.

i have attached screenshot of the error from within software and also the diagnostic log.

please can you point me in the right direction of you can.

Thanks for posting the diagnostic buffer, a lot of folks don't do that, and then we have to ask for it before we can help.

Your picture of the CPU error didn't come through.

I haven't worked with a 400 in a really long time, but my thoughts from what I can see from scanning through some of the diagnostic buffer:

1) Your Run/Stop switch seems be in stop for most of the messages; I never see it go from Stop -> Run. If the problem is that you can't get it restarted, doublecheck that the switch is in RUN.
2) I saw a couple messages that said DEFECTIVE. You probably want to contact Siemens tech support for more information. It could be that the right solution is to replace a module.
3) What is in slot 5? I saw a number of messages noting trouble transferring the parameters to that card.

thank you @mk42 for the quick response and helpful reply.

i have added the jpeg cpu error again, hope it comes through.

As mk42 asked, is the run/stop switch in the run position ?
If not, put it in run and again export the diagnostic buffer of the CPU.

There might also be a diagnostic buffer in the CP441 in slot 5. Usually Siemens S7 CPs have their own diagnostic buffers, but I have no experience with CP441.
Investigate and export this diagnostic buffer as well.

The CP443-1 also has a problem, there is a <!> symbol next to it in the online view.
Investigate the diagnostic buffer in the CP443-1 as well.
It may be that the problem is that is is not getting its configuration from the CPU.

I think that the problem is with the CPU, one of the CPs, or the rack.

Check this link for same issue :https://support.industry.siemens.com/tf/WW/en/posts/defective-internal-system-error-event-id-16-4550/178868?page=0&pageSize=10

Thank you for the replies,

yes the key switch is in the run position.
So you saying maybe a firmware update needed or possibly the cpu is an issue.

i will get the diagnostics and post it here.

As Jesper said, somehow the comms aren't getting from the PLC to the CP. It could be an issue with the PLC, the CP, a bad connection to one of the pins in the backplane, or a couple other things. With luck, it's a bug that's fixed by updating the FW for both the CPU and the CP.


Like I said before, I'd definitely recommend contacting Siemens tech support. At least in my country, you don't need any kind of support contract for basic phone/email support during business hours.

It is possible to be a problem with the backplane. Check that all the modules are seated properly on the backplane, with both top and bottom screw mounts secured.

The CP443-1 also has a problem, there is a <!> symbol next to it in the online view.

Click to expand...

The CP443-1 doesn't indicate a problem. This is the indicator that the CP is in RUN mode.

See below for installing S7-400 modules.

sigmadelta said:

The CP443-1 doesn't indicate a problem. This is the indicator that the CP is in RUN mode.

Click to expand...

You are right.
I thought it was an exclamation mark <!>, but it is an <I> with the "I" meaning "on".

I remember a similar problem in a S7-319 a few years back and Siemens had a special program block that would write information into a DB that would give them some more detail as to what was going on.

In the end, we had to replace the card, but there's maybe a possibility to save it.

Is this a new installation or are you looking into a problem that started recently?

I seem to remember having a similar problem some years ago, it turned out to be the 443 Ethernet card, have you got one of these installed. only a guess but that was our problem, fortunately, we had spares for every card but it was the last thing we changed. who would have thought it

Try to delete SDB then compile the HWconfig again then download.

You could also compare HWconfig setting with a simlar project, I met once the PN MRP configuration with 'empty' Domain, in this case CPU could not start. Actual this Domain is alway - mrpdomain-1 by default, I don't know why my project is 'empty'.