The Lookup Table (LUT) object performs a table lookup to create a relationship between a control input and a control output. For example, the LUT can convert vehicle speed value to gain.
The LUT performs linear interpolation between values. If the control input is below the minimum value in the x-axis, the LUT will output the minimum value in the table. If the control output is above the maximum value, the output is limited to the maximum value in the table. Every time the LUT receives an input on its control pin, it will output on each control pin output (one per element).
Currently, the LUT is a series of dimensional tables of resolutions from 2-200. The number of elements corresponds to the number of columns. The table resolution on columns is configurable by modifying the first additional variable ‘Table Height’. Both the dependent and independent table values are configurable in the GTT. The x-axis (control-input) needs to be in ascending order and is configurable through the tuning tool.
Example of LUT functionality:
Input axis in the following steps : 1, 10, 20
Output axis is set 50, 100, 200
The control input received is 0 – output is 50 because it is below the first input value, so it is clamped at the first output value.
The control input received is 10 – output is 100, it matches up directly with the table data so no fancy math here
The control input received is 13 – output is 130 (13 is .3 from 10-20 so we take .3 of the difference from 100-200 and add it to 100 (30 + 100)
The control input received is 5 – output is 4/9 * 50 + 50 or 72.2.
In the 2D mode – there is one control input, and the number of outputs varies based on the number of elements selected.
In the Index mode – there will be a second control input. This control input selects which ‘set’ of tables to use. Otherwise the modes behave the same. The number of sets is configured by the additional variable ‘LUT Depth’. The maximum depth is 8.