Failed to write to RSLinx OPC Server

[ILC]

Hi Experts,
I am using Matlab as an OPC DA Client to communicate with AB PLC rslogix5560. I can successfuly read from the PLC but when i try to write value from Matlab interface i get some quick Change and the PLC reset to the old Value. On the PC with Matlab i have another OPC Client namely RSView32.But RSView32 works just fine.
could someone have already face this issue?
Thanks
ILC

 

[Gadelric]

Cross reference the tag your writing to and see if something else is moving/copying data there as well. Your momentary change sounds like the data is being over written by something else in the program.

As mentioned in other threads, make a new tag and write your data to that tag. This being a fresh tag that isn't used in the rest of the program, would let you know if your set up is working.

If data can be written to the new tag without reverting to some other value, you know you com set up is correct and something in the program is changing the data your trying to write.
I have no exp with mathlab, but I recommend removing the coms and the plc program from the equation, as these are easy to check.

Happy Hunting,

Gad.

 

[ILC]

Thanks you Gad for your ínput. I will try it and give you a Feedback.
ILC

 

[ILC]

Hi Gad,
i check the cross reference of the tag and as you said it just a copy of the source tag. i had to Change the source in order to write successfully to the PLC.
Thanks you again.