By using tag names to access the value of a tag, Citect cannot logically ‘block’ several requests into one request and so the overhead cannot be eliminated. Started by jaxrpc , 18 Dec I ‘m sorry this is a bit vague but I havn’t used version 7 and I believe that it is very different as far as OPC is concerned to previous versions. It can automatically scan and find devices if you want it to, and that takes a lot of the configuration out of the way. With this in mind, Ci Technologies suggest that an OPC Server should handle the case where an access path is not specified.
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I am not sure if i got all the configurations right for my citect portion. Answer The Access Path is a server flient option that is intended to allow the client to provide a ‘recommendation’ to the server regarding how to get to the data.
Started by jaxrpc18 Dec Create an account or sign 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.
Is there any possibility to use the Access path in Citect? That your tag syntax is correct Note: I am listing the configurations, hope those who are familiar can verify it for me thanks. cluent
This will signifcantly load the network and have a corresponding affect on the performance of the Citect system as a whole.
Cigect this in mind, Ci Technologies suggest that an OPC Server should handle the case where an access path is not specified. As I said earlier these settings worked for OUR project in version 6.
Sorry forgot about the problem That the OPC Server can connect to the end devices. Question I citecr a customer who tries to connect to an OPC Server and they always get the error.
Citect OPC Client Connecting
Then check the Citect. Question The OPC specification uses tag names rather than physical addressing to request the value of a tag.
Wow, that’s an ambiguous error. This is because Citect has no control over whether the OPC Server optimises requests to the device in the most efficient manner. 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.
See this web site for further information: I ‘m sorry this is a bit citecr but I havn’t used version 7 and I believe that it is very different as far as OPC is concerned to previous versions.
Hi All, I am new to Citect 7. Citect does not allow the ability to specify access paths for items. This means that the response times shown in Citect for the standard drivers eg. 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 Citect.
Citect OPC Client Connecting – HMI & SCADA –
Register a new account. See KB Article Q The OPC specification isn’t exactly clear vlient 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.
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.
They may not even be available or may not be required in version 7.
How to connect an OPC client to your multi-cluster SCADA project
This measured time is usually insignificant compared with the actual response time from the PLC. It may be that an OPC Server allows items to be specified in a format similar to the native addressing format of the device, though this is not necessarily the case. You could use it to connect to the OPC Server and verify: This seems to indicate that the tag address has an incorrect item id, but the correct value has been entered.
By using tag names to access the value of a tag, Citect cannot logically ‘block’ several requests into one request and so the overhead cannot be eliminated.
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