800xA valves slow response
CPU Load and Cyclic load are both normal
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The AC 800M OPC Server have a logging facility that can be temporarily enabled to output when a write order starts and completes. The logging is controlled via a System Variable.
Up to and including 188.8.131.52
Set the system variable opcdadebugprint to true to enable logging (remember to set it to false when done!)
I 2020-12-17 17:02:35.364 AsyncWrite (2.0) started: 1 items in AdvDsOPCAdapterGroup11, TransID = 6
I 2020-12-17 17:02:35.416 AsyncWrite finished for TransID = 6.
I 2020-12-17 17:02:35.417 OnWriteComplete sent to client, TransID = 6, HRESULT = 0
Set the system variable opcda_loglevel to 1 to enable logging (remember to set it to 0 when done!)
I 2020-12-17 16:58:23.806 OPCDA IOPCAsyncIO2Impl::Write - succeeded. AllItemsOk=true, NrItems=1
I 2020-12-17 16:58:23.822 OPCDA AsyncWriteCallback, OnWriteComplete - succeeded
In both cases, the output is written to the OPC server log file:
C:\ABB Industrial IT Data\Control IT Data\OPC Server for AC 800M\LogFiles\session.log
A write can be delayed if the controller is highly loaded or not properly task tuned. Tuning constitutes insertion of an "offset" (delay) between tasks. 10-20 ms is a minimum recommended figure.
Write performance can also be set back if Automatic Saving of Cold Retain is done. It is recommended to not save more often than a couple of times per day and use an offset on the secondary OPC server; E.g. setting server A: 24 hours interval, 0 hours offset and server B: 24 hours interval, 12 hours offset will result in two savings per day.
The actual visible feedback in the operator workplace is not seen through the write completion, it is sent as updates on the OPC subscription. If you have a trend log, you can read the time when the valve signal is moving.
More information is required to assist you...
Don't hesitate to file a support case with your regional ABB Support Center.
Are you sure this is system 800xA related?
In my opinion, field equipment failure/malfunction is far more frequent than internal system issues.
If you see slow response only from, as you mention Open/Close valves, I would check mechanical, pneumatic or hydraulic systems first.
Can you test some other process equipment?
Or is the system 800xA sluggish, then a would check recent activities, updates, downloads etc.
Are the valves in question spring-loaded? Actuator?
If it is just a digital output to open valve, try force it (hardware or software).
Your description is a little thin...
(Not to mention; version, controller, I/O, field network etc)