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Does UniOPC support historical data access (HDA)?


If so, is it possible to access data tables in memory and on SD card? How?

If not, what is the recommended way to do a fully automized download of logged data?


I am using Vision OPLCs.


Thank you for clarification,


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Hi Ronald,

UniOPC Server is compliant with the OPC Foundation's Data Access Custom Interface Standards through to Version 3.00.

Unfortunately, is does not support HDA.

It is also not possible to read data directly from the SD card.

One possible way to automate this process is as follows.

1. Create a subroutine on the PLC that will be initiated either periodically or by the SCADA.

2. In the subroutine, extract the data from a data table to a vector of MI's (using the "read row" or "read column" commands).

3. send the vector to the SCADA. If the vector is longer than 32 MI's, you will have to send it in chunks.


It is not the most elegant solution, but it should work.

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