I have a heartbeat at each of the 6 services that is changing every 5 seconds which triggers a write to another tag. Also at each service I have 'data collect' bit that triggers a readmultipletag of roughly 15 different tags, insert into a mssql database and then a write to a tag. That transaction occurs about once every 30 seconds at each service.

I've noticed that with the 6 services that I run, it appears that when I run them all, it looks like it start missing events in all the services (too much load on the one dll?) Overall performance looks like it really suffers.

I went with this approach (6 services) because for this application there are six separate operations that all require their own high priority for heartbeating and performing handshakes with the PLC. Would it be better to have one service that is subscribed to all the heartbeats and handshaking for all operations? Logically I guess that never made much sense to me so I didn't give it any thought. I'd like to hear what you think though.

I'll keep an eye out for this. I wasn't watching the easy opc process. It looks like I can just restart my php services and they start functioning again for a limited time. I'll keep an eye on the easyopc service/process though now and let you know.

Nevermind, it's still not working. Just took longer to crash this time...

All the services crashed in about 3 hours with this error when writing one bit:
exception 'com_exception' with message 'Error [0x800706be] The remote procedure call failed

I've done what you recommended to do earlier, but it doesn't look like it has solved the problem.

Okay that seems to have taken care of it. I've had them all running over 3+ hrs and it seems to have not skipped a beat which is great.

However, now the heartbeat seems so slow. The heartbeat I am doing with the PLC is the PLC increments an integer tag that I'm subscribed to. On change I simply set a different integer tag equal to what the PLC set. I'm noticing that sometimes after the PLC changes, it takes sometimes 3 seconds for the other tag to update.

Is this Isolated mode causing performance issues? Is there a setting in the EasyOpc Options to make this more responsive?

I guess I'm a little confused on setting isolated to true on the EasyDAClient. Isn't that only available on the EasyUAClient?