danish202

S7 300 Profibus fault

8 posts in this topic

Dear All,

We are in need of your expert opinion.

One of the nodes of our Crane's Cabin gives a station failure problem, due to which whole Crane shuts down. we have done everything from replacing Dp connectors to changing Profi cables, swapping modules with other stations, changing Power supplies but the problem remains the same.

Following are the system details,

1. CPU S7 319 F3 fail safe

2. IM 153 interface module

3. OLM module for signal conversion fibre to profibus from main CPU.

 

We have several nodes after OLM but fault was persistent with 3 nodes. After comprehensive working, it came down to just one but still not diagnosed. I will also upload the diagnostic buffer if needed.

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You need seimens step 7 software and  try to troubleshoot online.  go to the diagnostic buffer, and it will display which module or any that causing the problem. or go to the hardware configuration and online, you can see from there the modules condition, the module failed to communicate will be mark with x. is your CPU SF led is ON? what is the condition of the CPU? any red led is on. i mean the BF? SF?. try to secure the software, it will not take time troubleshooting if you have the software. 

Edited by Jairus

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Dear Jairus,

We have the software. We have checked Diagnostic Buffer 100 times.One node node goes off for just a moment, hardly for a milli second & then comes back, checked through Diagnostic Buffer. This happens sometimes in a hour, sometimes in 6-7 hours. We have replaced all modules of that particular node but the problem is persistent. I will upload the diagnostic buffer in a while.

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Below is the fault detail of diagnostic buffer

 

Event 9 of 211:  Event ID 16# 39C4
Distributed I/Os: station Failure
Address of the affected DP slave: station number:   17
DP master system ID:      2
Log. base address of the DP slave: Input address:  8170
Log. base address of the DP master:   8191
Requested OB: Rack failure OB (OB86)
Priority class: 26
External error, Incoming event
08:16:49.888 AM  12/10/2017

 

Regards,

Danish Abbasi

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From the looks of this address 17 is dropping out, I would look at the shielding and terminating resistor on the profibus. A broken shield will cause this problem...

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Dear Patch1,

Shielding is thoroughly verified and has been connected externally with Ground. This problem, sometimes arises within minutes while at other times after some hours.

There is no specific pattern of time or operation, that's why its causing us head ache. 

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Is there any FM card or any other module in the slot under the station IM 153?  In my experience. example the FM  card will alarm due to the encoder was faulty. Your IM 153 will goes to System fault or SF alarm, and that will appeared to your diagnostic buffer. So try to consider also the module under your IM 153, maybe one of those module in the station cause the alarm. 

Edited by Jairus

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On 13/12/2017 at 7:59 PM, danish202 said:

Dear Patch1,

Shielding is thoroughly verified and has been connected externally with Ground. This problem, sometimes arises within minutes while at other times after some hours.

There is no specific pattern of time or operation, that's why its causing us head ache. 

I had a problem of profibus node going out of communication for very short time (matter of milliseconds). It wasn't a big deal in my system such short loss of comms so I called OB86 in my program to avoid going in to stop mode. Maybe this can help you. More about diagnostic with OB86 you can find here:

https://support.industry.siemens.com/tf/WW/en/posts/rack-station-failure-and-ob86/27733?page=0&pageSize=10

 

My symptoms were same as yours but we never found out the reason why it went to stop..

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