Step7 - Profinet

lostcontrol · Jul 2, 2021

Hi,

I am setting up a new Profinet slave device. After much mucking about, finally have it working to my PLC.
But, if the device is powered off etc, it faults the controller. How can I solve this?

Thanks
LC

JesperMP · Jul 3, 2021

Look in the diagnostics buffer of the CPU.
It will say which error-OB is missing to not have the CPU fault.

lostcontrol · Jul 3, 2021

PROFINET IO: station Failure
I/O access error, reading
STOP causing by I/O access error (OB not loaded or not possible, or no FRB)
OB number : 1
Module address : 104

Is there an OB that will be called, that can stop the CPU from faulting, as this would grind the machine to a halt whit it not required.
I have OB86, reading this says OB82 (https://support.industry.siemens.co...ob-not-loaded-or-not-possible-or-no-frb/47105)

I completely understand what is occurring & why, but dont want it to stop the process.

sigmadelta · Jul 3, 2021

Create and download OB122 (I/O access error)

lostcontrol · Jul 3, 2021

Create and download OB122 (I/O access error)

Ok, will that prevent the change to STOP?

sigmadelta · Jul 3, 2021

For an I/O Access error - yes.

There is no global OB to prevent stopping the CPU, but OB 82, OB86 and OB122 should prevent stopping due to hardware in your case. If you look up "Organization Blocks" in Step 7 help, a list of all OBs should appear. What is your CPU model? Not all OBs are available for all CPUs.

lostcontrol · Jul 3, 2021

sigmadelta said:
what is your cpu model? Not all obs are available for all cpus.

im151-8

sigmadelta · Jul 3, 2021

If you look at the Module Information online, one of the tabs lists all available OBs in the CPU.

sigmadelta · Jul 3, 2021

I found a useful link for you:

https://support.industry.siemens.co...tatus-when-a-remote-i-o-fails-?dti=0&lc=en-US

lostcontrol · Jul 3, 2021

sigmadelta said:
For an I/O Access error - yes.

Just done & tested, works as expected!

Now my next challenge is to detect that the error has occurred, but perhaps I should do some reading

sigmadelta · Jul 3, 2021

You can put any code you wish in the OB blocks. You can set a bit for example...or you can actually read out which module/rack caused the issue... That's a bit more complex... but not too bad. You could simply move the value you want into some address/tag... The key is, which value? Help files on each OB is in Step 7 help. Try selecting an OB in the blocks folder and press F1.

sigmadelta · Jul 3, 2021

You may also want to look up "report system error" which sends diagnostic messages to a Siemens HMI.

Lare · Jul 4, 2021

lostcontrol said:
Just done & tested, works as expected!

Now my next challenge is to detect that the error has occurred, but perhaps I should do some reading

you can do it on your OB-blocks, but error state is only one plc scan valid on OB blocks.

For 300 (and 151-8, which actuallu is 300 series) FB126 is way to go. It can be used lot more than errors states (like disabling stations).

Some of FB126 is not described thought and it helps if you can also run WinCC project of screens and look how errors are showed on WinCC with FB126 block. (It needs block call from several different OB blocks.

https://support.industry.siemens.com/cs/ww/en/view/98278878

Step7 - Profinet

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