6. Function blocks
6.1 Manufacturer function blocks
Other
Retention
The function block does not recognize retentive data.
PM function block example: How the operating mode affects the results
Say that the following characteristic curve needs to be implemented using the PM
function block. To do this, 32 mapped values are defined in the reference value table.
Fig. 187: Example of a characteristic curve for the PM function block
Example of a reference value table in which QV values are mapped to I1 values
 I1  QV
1
0

0
2
2

2
3
4

3
4
8

4
5
16

5
… …  …
31
26  10
32
30  12
The following table shows how the operating mode affects the values at function
block output QV if the characteristic curve from the example is implemented using
the defined reference value table. With the following values at the function block
input:
Value
at I1
Value at QV as a function of the
operating mode
1
Interpolating: 1
Next higher value: 2
Next lower value: 0
Nearest value: 2
3
Interpolating: 3
Next higher value: 3
Next lower value: 2
Nearest value: 3
5
Interpolating: 4
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