RDA (Realtime Data Acquisition)

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The RDA functionality is used in order to read values which were archived in the control and to save them in a zenon archive. A typical application for this are archiving tasks of a control which is not permanently connected to zenon.

1. Defining variables in the PLC

A seperate, continuous, linear area has to be created in the PLC for each RDA variable.

In order to avoid problems, the data type of the variables should not be smaller than the one in which the PLC is organized!

The first variable of the area in the PLC reserved for the RDA serves as a switch for the transfer process. I.e. if its value is set to 1 by the PLC, the following values – as defined in the header (see below) – are loaded into zenon and archived. Then the driver sets its value back to 0 automatically.

2. Defining the variable in zenon

In zenon you can define the variables as usually. The variables have to come from a continuous, linear area in the PLC.

Keep in mind to set the property "Recording type" in "Additional settings/Harddisk data storage" to "postsorted values (RDA)".

3. Creating an archive in zenon

Create an archive and select the RDA variables. The defined archive has to be spontaneous.