Heartbeat from OPC Server Interface?

[zoomable]

All,

How would I implement a heartbeat mechanism from a client app that is using OPC to communicate to PLC (Siemens S7-1200, integrated OPC server)?

Would it be as simple as having the client write a byte every T seconds, and some PLC logic that monitors it?

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[busarider29]

That should work. I did something similar and it works fine. I believe I had it so that the app was incrementing an integer value in the PLC every 500ms. The PLC checks the value every 1s and if the value hasn't changed since the last check/read, then there's been a communications disconnect.

 

[cardosocea]

You're on the right track.

Remember that some OPC Servers (I've used Kepware, IGS and Applicom) have data that you can read of them to determine whether you're connected to or not. IGS (and I imagine Kepware) would have tags made available with telegram counters that you could read off of the OPC.

 

[zoomable]

Awesome, thanks guys.