I have a question regarding your OPC server and its update time.
We have in our plant some machines running Codesys RTE and gateway and OPS server.
Our symbol file has approximately 4000 entries. These are used to drive the visualisation screen.
With this many symbols we find that the best update rate is approx 100ms.
We would also like to collect a smaller amount of data, something like 16 boolean variables but at a much faster update rate.
I am not getting a fast enough item update rate from the server.
Any ideas how I can get an update rate of 10 to 20 ms to a 2nd OPC cliect?Answer
A constant update rate of 10 to 20ms is almost impossible. Beside the fact that the communication is already busy there are several other reasons which prevent it in general:
- Windows applications can be interrupted anytime, earliest recall after 10ms
- overhead by several partners in the communication chain (OPC Client ßà OPC Server ßà Gateway Server ßà PLC)
- OPC architecture isn’t build for such a fast communication
If you really need it, we can show you a solution which is realized with the PLCHandler, a fee required C++ class which facilitates communication between a client (e.g. visualization) and the PLC. As the data is stored in a buffer on the PLC you can reach little update rates and cycle consistent data. But you must create an own windows application.Back to FAQ overview