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7.2 Read and write curves over PROFIBUS (acyclically)
It is possible to read or write at multiple slots in the slot index directory. The implementation is the
same in both cases, and requires a structured procedure.
7.2.1 The curve is to be read.
1
Load the curve into the fieldbus card through a write access to index 10.
2
Query the last measured value for the curve (
end of the curve) through a read
access to index 10.
3
The curve can now be read out in coordinate groups of up to 200 coordinates
each:
Coordinate group 0: Measured value 0 … 199
Coordinate group 1: Measured value 200 … 399
Coordinate group 2: Measured value 400 … 599 … etc.
4
The number of the desired coordinate group is entered through a write access to
index 19. Since we want to read the beginning of the curve, we enter a 0.
It is now possible to read curve values no. 0 … 199 (at present we have selected
coordinate group 0) at the indices 20 … 219.
5
Coordinate group 1 (values 200 … 399) is now read under index 19.
It is now possible to read curve values no. 200 … 399 at indices 20 … 219.
6
After this, coordinate group 2 (values 400 … 599) is read under index 19.
It is now possible to read curve values no. 400 … 599 at indices 20 … 219, and so
forth.
7
The coordinate groups can be read out in any desired sequence.
8
Only curve values that are smaller than or equal to the number of the last
measured value (which was read at index 10) may be read out.
