Lookup table (0x80n1:21 “lookup table length”)
Using the lookup table offers the option to perform a transformation of the input values within the terminal. In the task cycle the terminal uses interpolation points to return a corresponding predefined output value for each input value. This allows reconciliation of non-linearities in the signal sequence.
- The lookup table is enabled via index 0x80n0:0B "Enable lookup table"
- The total length of the interpolation points to be used is entered in index 0x80n1:21 "Lookup table length". A maximum of 20 X/Y value pairs can be entered, which corresponds to a maximum lookup table capacity of 40 values.
- The respective X and Y value pairs are to be entered in object 0x80n5 "IND Scaler Settings Ch.n". Note the following regarding the entries in the lookup table:
- The odd subindices (1, 3, 5, ...) refer to the corresponding X-values, i.e. the values measured by the sensor
- The even subindices (2, 4, 6, ...) refer to the corresponding Y-values, i.e. the values to be mapped in each case
- Each X-value must be accompanied by a corresponding Y-value. Within the interpolation points the signal is interpolated; above/below it is extrapolated with the last/first available slope.
Index (hex) | Name | Meaning |
---|---|---|
Enable user lookup table | Enable lookup table | |
Lookup table length | Number of x/y value pairs in the lookup table | |
Scaler Value 1 | Interpolation point / lookup x-value 1 | |
0x80n5:02 | Scaler Value 2 | Interpolation point / lookup y-value 1 |
… |
|
|
0x80n5:27 | Scaler Value 39 | Interpolation point / lookup x-value 20 |
0x80n5:28 | Scaler Value 40 | Interpolation point / lookup y-value 20 |