OPC Async Write Slow

[Software_Monkey]

Hi,

Hi,

I am using a CFP 2020 network module over Ethernet with the National Instruments OPC Fieldpoint server, When I perform async writes to the LED's on the CFP2020, sometimes it works instananeously but at other times it appears to take 1 or 2 seconds for the writes to take effect. I have tried the same client connected to Wago I/O modules over Profibus and it is OK so it doesnt appear to be a client problem.

Changing the OPC update rate has no effect (which of course it shouldn't).

I get the impression that the writes are being cache'd somewhere but I could be totally wrong here!

Is there some other setting in the network module or the NI OPC server that needs to be changed?

Thanks

Tony

[YatinM]

Hi Tony

I have attempted to replicate this issue in our lab using our cFP 2120 controller. The LEDs seemed to perform correctly and instantaeneously even after some 20-30 operations. The writes should not be cached anywhere and should operate as you have commnaded, How are you communicating with the cFP? Did you save the .iak file via MAX and use the config with the OPC server?

In our lab we have a cFP 2120 controller with a full 8 module rack. All the modules are plugged in (AI, AO, PWM, TC), this doesnt seem to slow any of the write operations down. Could there be a chance that the hardware you are using could be at fault?

Kindest Regards

YatinM

National Instuments 

[Software_Monkey]

Thanks for the reply.

I got hold of the loan kit again this week and when I tried it, it seemed to be OK and so I do not know what the problem was. The only difference was that the loan kit originally had a TC-120 module in it, but now it hasn't but I would be surprised if that was the cause as it was reading OK. Your comment about your system is reassuring that it isnt an 'expected thing' with a full module rack.

I did save the .iak file but I am not sure if I need to do anything else to ge the OPC server to read it and configure itself.

So, all in all its a mystery and I can't replicate it myself now but thanks again for the reply.

Regards

Tony

[YatinM]

Hi Tony

Im glad to hear that the issue has not arisen again. Like I said it is not an expected occurance even with a full rack of modules.

All the best

Kindest Regards

YatinM

National Instruments