Dear colleagues!

Is it possible to implement OPC write-commands only at the end/beginning of the OB cycle?

I mean OPC waits for the end of OB1 and then writes to DBs.

For example using:CPU 417-4 CP 443-1, OPC SimaticNET v6.4

Best Regards,

Dmitry

I suggest checking "7.2.1 Consistency of communication blocks and functions " of this manual for more information.While using communication functions in source and target with proper signals, consistency of data can be ensured by checking feedback of receiving function.For OPC,I think you need to implement such a strategy in your program.

Consistency of communication blocks and functions

With S7-400, communication jobs are not processed in the cycle control point but rather in fixed time slices during the program cycle. The system can always process t he data formats byte, word and double word consistently, i.e. the transfer or processing o f 1 byte, 1 word = 2 bytes, or 1 double word = 4 bytes cannot be interrupted.


Best regards,
Hamid Hosseini