I have a proble in the communication between a PLC Omron and Labview, I esplain now the background:
I`m using a Omron PLC CJ1W CPU 13ETN to control an application and I would use labview 8.6 as as interface to control and monitoring the state of the process.
The PLC is connected into a Ethernet network, and I`m using NI OPC Server to read and write some data memory of the PLC trought Labview.
I have creaded a client in Labview who is connected to the NI OPC Sever, I have created about 110 Shared variable that are connected with the Data memory of the PLC throught the NI OPC Server.
The Labview program has a VI that read some shared variable and display the value and write some other.
Generally every hour that the system run, the Variagle Engine crash and I`m obliged to close the application and restart again.
Please can I have an help?
Here attached are the error message
thanks in advance
Vincenzo, has contacted NI UK Support regarding this issue.
I will be working with him to try and resolve this issue. If anyone has any suggestions or input for this issue, from past experience, then please do feel free to post here too. Otherwise, I will update this post in due course.
Vincenzo, do you have a PC with duo core processor? If so, try to disable the duo core function in the BIOS, this might help!
Let me know if you have update on the issue!
Thanks for the post.
We have managed so far to isolate the issue to writing to the plc. When the application only reads (to either plc) it all works fine. When the VI contains writes (the Omron is the only one which does this) the error occurs at some time.
I have suggested two points:
1) Testing just the writes - does it error?
2) Use two while loops instead of one, to read / write to OPC tags.
Do you feel the multi-threading issue would affect these writes?
The results of the above mentioned tests should indicate whether its an plc configuration issue (for writes) or the design of the application to handle writes & reads.
thanks for the help, I have done some test as you suggested and that are the results:
- I have tried the application with read only shared variables and the Labview application doesn`t give problems
- I have tried the application with write only shared variables and the Variable Engine crash every 10 or 15 min max. The NI OPC server works fine even after the crash, I have created a Quick client in the NI OPC Server and it works fine even after the crash.
So know I think this issue is between the NI OPC Server and Labview and it is due only whenever Labview try to write a value in the PLC Tag.
Moreover I would try to test only one core of the CPU, but I`m not able to disable one, please David can you suggest how to proceed?
Thanks in advance
Thanks for the post.. the single core is only supported on some machines. What PC are you using? Have you looked online from the manufacture for information on this.. I am afraid all BIOS are different. On my machine, Dell, Its under Advanced.
your suggestion was right, I have disable one core of the CPU and everything goes well.
Thanks for the help to everybody
Glad to hear that everything works fine now!
Might you have further questions, feel free to post it!
Hi to all!
Glad to hear that NI guys let you solve this issue
About your last question, i suggest you to look what Windows API let you disable the number of processor in your machine. Then the next step would be the implementation of the LabVIEW code that programmatically lauch this API (using the System Exec.vi function) and let you run fine your application. I can't point you to a good web source due to differences between mother boards, but i figured that you should easily find the commands you need according to your hardware.
Please let me know if you need additional help.