SV5.1 Fp4 RevD Ru1-When PLC connect communication with ICS fails causing all graphic pages freezes & update 30sec
Hello,
Whenever PLCconnect OPC communication fails with ICS OPC server then that time all graphic pages(Process & OPC linked pages) gets freeze & it will take minimum of 30sec to update data & page navigation also taking 20-30sec as well.
If communciation is OK then all graphic pages will work normally with normal update rate wihtout any problem.
Why this adverse effect happening when PLCconnect OPC communication fails & communication also failing at an interval of once in a week..we are using SV5.1 FP4 RevD Ru1 with Infi90,AC800M,PLCconnect(1oo2) we are using.
Please kindly let us know any fixes available for this.
Answers
I would say workplace delays/freeze may be expected if the source OPC server is not acting as it should.
Navigation between displays forces synchronous* AddItems() and RemoveItems() calls to be posted from the workplace to all OPC sources. The timeout is 30 seconds.
If one or more OPC servers are not acting as expected, e.g. stops responding on above mentioned calls the OpcDA Connector and workplace may block until released by timeout.
*) OPC Foundation DA 2.05 standard dictates synchronous methods.
The design of System 800xA is that each OPC DA client drawing data through the 800xA framework, e.g. a graphic display open inside a operator workplace will have its own dedicated communication channels to all OpcDA Connector service providers required to feed the subscription.
If one OpcDA Connector does not receive updates from the source OPC server, it should not prevent other connectors to continue deliver data to the workplace.
However, a workplace trying to cancel a frozen subscription may block if the source OPC server (via the OpcDA Connector service) does not expedite the RemoveItems() call in a timely fashion.
In my own experience, such blockages are *not* seen when using the core AC 800 or auxillary AC 400 OPC Servers.
I recommend filing a support case with your regional ABB support center to have things sorted out.
I also recommend probing the source OPC server with some external OPC DA client to verify if freezing behavior is observed there as well. In this case, the vendor of the source OPC server should be contacted.
I can not answer for how PLC Connect will handle a frozen source OPC server; I would expect clients "on the inside" (e.g. the OpcDA Connector) to not suffer from this. But this theory must be verfied or rejected by PLC Connect R&D.
From a system perspective, an OPC Server in trouble should flag an abnormal status on the GetStatus() call. This call is attempted every 5th second by the OpcDA Connector service; abnormal status will lead to immediate process abort which in turn will trigger immediate failover to the next available service provider. There is also a timeout which will abort the connector if no answer is received. Please monitor the [Workplace Structure]Web System Workplace:System Event List for diagnostic messages from the OpcDA Connector service, e.g. "OPC Server has stopped!".
System 800xA contains *plenty* of logging mechanisms for the OPC DA framework. I teach some of them on my E143 expert workshops here in Västerås.
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