Hello,
thank you.

It's good that you found this workaround, because it also tells me a bit more - although still not enough - about where the problem might be. It appears to be related to automatic session opening/closing.

If you want to keep your 5-seconds reading interval, can you please try a different workaround: Set the session HoldPeriod property to much smaller value (500 or 1000) - opclabs.doc-that.com/files/onlinedocs/QuickOpc/2022.1/User's...sionParameters~HoldPeriod.html .

Regards

Hi,

Version is: 5.63.246.1

 

Hello.

Which QuickOPC version are you using please?

Regards

The inner exception the system is giving back is: "No connection could be made because the target machine actively refused it".
It happens with 2 different PLC brands (Siemens and Beckhoff). 
Also, I found that increasing the delay beetween 2 "Read" to 10 seconds, the problem disappears.

Hello.

You are right that the expected behavior is that QuickOPC should reconnect, without extra effort on your coding side. So we need to investigate that.

First thing I need to know is, when you receive the null value, whether the .Exception in the UAAttributeData is also null, or - when it is not null - what are the exception details.

Best regards

Hello,

I'm facing a problem with OpcLabs 5.63.
In my windows service I'm reading a PLC tag every 5 seconds with this instruction: "UAAttributeData attributeData = easyUAclient.Read(opcServerName, itemName, UAReadParameters.FromDevice);" where easyUAclient is an instance of EasyUAClient class.
I found that after a PLC reboot the Read method is always returning null value. If I restart the windows service, everything is going to work fine, but of course I cannot restart the service every time the PLC is reeboted.
Is it there any way to restore the connection or something like that? 

Thank you!