1/25/2022 12:54 AM | |
Joined: 9/27/2006 Last visit: 9/25/2024 Posts: 12282 Rating: (2685)
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Hello tiger; May I ask if you have loaded OB 86 in your PLC program? Note that this is the OB requested by the CPU.s operating system when it faces this kind of distributed rack failure. One of the advantages of having OB 86 inside the CPU is that for a Profibus I/O rack failure the CPU should continue in RUN, with a BF LED active. That would give you time to find and fix the problem you are facing. You have a CPU S7-317-2DP, programmed under Step 7 v5,x, as per your screenshot. This FAQ should give you nteresting information on your problem. - Which organization blocks do you have to load into the CPU to ensure that the CPU does not go into the "STOP" status when a remote I/O fails? https://support.industry.siemens.com/cs/us/en/view/19350076 The following document has been much help to many facing issues on Profibus-DP. It provides guidance on diagnsing a faulty Profibus network. It is short and to the point, pointing out common faults and their solutions. Note that the most common fault you should check is the status of the termination, on the first and last physical station in your network. https://us.profinet.com/top-5-reasons-your-profibus-network-failed/ Hope this helps, |
Last edited by: dchartier at: 01/25/2022 00:56:07 |
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1/29/2022 4:01 PM | |
Joined: 10/18/2018 Last visit: 3/6/2024 Posts: 13 Rating: (0) |
Hi Daniel, Please find attached txt file. Thanks in advance AttachmentDiagnose.txt (494 Downloads) |
1/30/2022 9:43 PM | |
Joined: 9/27/2006 Last visit: 9/25/2024 Posts: 12282 Rating: (2685)
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Hello tiger; I have looke d at the contents of your diagnostic buffer; unfortunately, it is very small, cofigured to log a maximum of 10 messages. This does not give us much information to work with. What it does indicate is that Profibus node 5 has lost communication with the CPU at one point (and returned), and that during the period it was online the progam tried to access PIQ 540, PIW 542 and PIW544 without succes. In your hardware configuration, can you identify node 5, and the I/O addresses linked to that node? Do they correpond to the information from your buffer? As stated earlier, your buffer is not long enough to tell us if other stations lost communictions or when they did. The screenshot below shows you how to extend the size (in messages) of your diagnostic buffer, I suggest you start by changing that to the maximum number of messages supported by your CPU, 100, 250, 00 if possible. Then run the CPU for few hours and then generate a new text file we can look at agin. The image is taken from S7 troubleshhoting training document you ight want to look at in the meantime. it might give you hints on ways to find the surce of your problems.: http://www.infoplc.net/files/descargas/siemens/infoplc_net_sitrain_14_troubleshooting.pdf One more suggestion: connect to the CPU, open your hardware configuration and go Online. You will see all the modules that are in fault, including your Profibus nodes, with a red error icon (see page 16 of the document linked above). Tha mght give you mre indications on the faulty nodes in your system. If you double-click on the fault icons in Online view it will show you the local diagnosticc buffers with additional fault information. Hope this helps, |
Last edited by: dchartier at: 01/30/2022 21:51:55Last edited by: dchartier at: 01/30/2022 21:59:10 |
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1/31/2022 2:41 AM | |
Joined: 2/6/2009 Last visit: 8/19/2024 Posts: 939 Rating: (118) |
Hi Tiger, Sometimes it looks simple but complicate to troubleshoot with communication issues which occurs occasionally. As @Daniel mentioned, the diagnostic buffer looks very simple to indicate the communciaion failure the DP slave. This may look very basic questions, but its always better to check, 1. Please confirm the same DP slave fails always? Slave 4? 2. If so, Is this the last on the profibus network? 3. Is the distance winthin the profibus network capability for the buad rate selected? 4. Is there any intersecion of power cable/machine vibraion/wet area in the profibus network? Try using the electrical conduit for the profibus cables before changing the cable completly? At last, try using the profbus diagnostic tools for the network analysis |
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