AC500 PLC Stopping without any Error
Hi,
We are facing an issue with AC 500 PLC. Normally, when plant is in operation and all of sudden, PLC stops and all machinery goes offline. On further troubleshooting, we found that no errors are recorded and only 100% indication is shown in CPU statistics window. Now plant is again in normal operation and CPU usage is around 3%. Can you please support us understanding and resolving this peculiar behavior? Snapshots are attached herewith for your reference.
Asked 6 months ago
Answers
0
I haven't used PM595 but i have noticed similar Max 100 % load indication on other AC500 processors. This should be fine if your Avg load isn't too high and you know that inside your program you don't have a situations where suddenly you switch a lot of code into execution. Example would be: if normal situation-> do nothing, else >50k lines of code. Also your task cycle time is 500 ms and PM595 should be able to handle all code (very large number) within this interval.
If you have a normal error then you should be able to connect Automation Builder to PLC. Task watchdog expiration is a normal error and you should be able connect the PLC. If you can't then you have some sort of firmware crash.
You need to do some investigation. I would probably start with:
1. How long was the system running before these issues started?
2. Is there anything common between the crashes?
3. Comment "Error Led turns on" do you mean that the Run led is still on but there isn't any execution?
4. Do you have the display for the PLC?
5. From the Information.png i assume you are using Automation builder 2.0.x. Newest version is 2.2.5, have you read all the Automation Builder release notes and checked if anything might be related to your situation?
https://new.abb.com/plc/documentsandd... or
https://library.abb.com/en/results
6. Do you have modules at the I/O-bus and their installation is ok? No weird extensions or other issues?
7. Do you have some type of "special" communication at the Ethernet, Profinet or COM ports?
8. Do you have while or long (duration) for loops in your code?
9. Maybe you could create your own diagnosis with the Task Configurations System events and try to narrow down possibilities.
10. ...
If you have a normal error then you should be able to connect Automation Builder to PLC. Task watchdog expiration is a normal error and you should be able connect the PLC. If you can't then you have some sort of firmware crash.
You need to do some investigation. I would probably start with:
1. How long was the system running before these issues started?
2. Is there anything common between the crashes?
3. Comment "Error Led turns on" do you mean that the Run led is still on but there isn't any execution?
4. Do you have the display for the PLC?
5. From the Information.png i assume you are using Automation builder 2.0.x. Newest version is 2.2.5, have you read all the Automation Builder release notes and checked if anything might be related to your situation?
https://new.abb.com/plc/documentsandd... or
https://library.abb.com/en/results
6. Do you have modules at the I/O-bus and their installation is ok? No weird extensions or other issues?
7. Do you have some type of "special" communication at the Ethernet, Profinet or COM ports?
8. Do you have while or long (duration) for loops in your code?
9. Maybe you could create your own diagnosis with the Task Configurations System events and try to narrow down possibilities.
10. ...
Answered 6 months ago
0
Hi,
Please set Task priority to 11 instead of 10. Download the modified program and place the PLC in RUN mode.After doing this, observe whether the PLC experiences the same issue again.
Regards
Rahil
Please set Task priority to 11 instead of 10. Download the modified program and place the PLC in RUN mode.After doing this, observe whether the PLC experiences the same issue again.
Regards
Rahil
Answered 6 months ago
by ak Rank: 173 on 8/11/2020 11:15:10 AM | Like (0) | Report
What happens when the PLC stops? Is it a crash? How do you recover from the PLC stop? Do you reboot the PLC (switch off power)? How is your task configured?
by basit.javed Rank: 1641 on 8/11/2020 10:15:24 PM | Like (0) | Report
When PLC stops its ERR LED turns on. It appears to be a crash but reason for the fault is still unknown as no errors are recorded in diagnostics window. I tried to connect Automation Builder with PLC but it stops working as soon as I go online and open statistics window. Only possible way is to reboot PLC with a power cycle.
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