Question What is OPC? That the OPC Server can connect to the end devices. I am listing the configurations, hope those who are familiar can verify it for me thanks. That your tag syntax is correct Note: How does this affect the performance in Citect?

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Citect OPC Client Connecting – HMI & SCADA –

OPC Explorer is not a replacement for Citect, it’s just used for testing. The OPC specification isn’t exactly clear as to whether it is legal for the OPC Server calls to fail if an access path is not specified, but it does go as far as saying that by “convention” a server should select an access path if one is not provided.

See KB Article Q As Citect cannot block individual requests when using tag names to access the tags values, each Citect Client will request each tag individually across the network.

This is because each request has a specific overhead in time independent of how many tags are being requested, so by making one larger request instead of many smaller requests reduces the average overhead per tag.

With this in mind, Ci Technologies suggest that an OPC Server should handle the case where an access path is not specified. While the exception reporting nature between the Citect OPC Client and the Server reduces or negates this concern at this point, performance may still be degraded at two places: It can automatically scan and find devices if you want it to, and that takes a lot of the configuration out of the way.


Some other method of comparing the drivers should be used.

We have a large project in version 6. OPC Explorer is freely downloadable http: This is because Citect has no control over whether the OPC Server optimises requests to the device in the most efficient manner. Answer When Citect reads tags from a PLC, it is sometimes quicker to request a block of tags which includes several of those needed by Clkent. Posted 24 Dec Sign up for a new account in our community.

I am not familiar with ver oc.

Q Citect OPC Client FAQs

Create an account or ciitect in to comment You need to be a member in order to leave a comment Create an account Sign up for a new account in our community. This measured time is usually insignificant compared with the actual response time from the PLC.

Posted 18 Dec Vlient am listing the configurations, hope those who are familiar can verify it for me thanks. Share this post Link to post Share on other sites. This seems to indicate that the tag address has an incorrect item id, but the correct value has been entered. Question Do the ‘Response times’ shown in the Citect kernel eg.

I ‘m sorry this is a bit vague but I havn’t used version 7 lpc I believe that it is very different as far as OPC is concerned to previous versions. It’s available as a free 30 day demo here: This will signifcantly load the network and have a corresponding affect on the performance cietct the Citect system as a whole.


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Posted clieny Dec Question I have a customer who tries to connect to an OPC Server and they always get the error. How does this affect the performance in Citect?

Answer The Access Path is a server specific option that is intended to allow the client to provide a ‘recommendation’ to the server regarding how to get to the data. I am not sure if i got all the configurations right for my citect portion.

Citect OPC Client Connecting

By using tag names to access the value cktect a tag, Citect cannot logically ‘block’ several requests into one request and so the overhead cannot be eliminated. They may not even be available or may not be required in version 7.

Started by jaxrpc18 Dec As I said earlier these settings worked for OUR project in version 6.