Fixed-Point Blockset

Simulation 2: Global Override

Prior to using the automatic scaling tool, a global override with doubles of the fixed-point data type is performed for every block. Using this feature, you can obtain ideal simulation limits. Additionally, you must log maximum and minimum simulation values for all blocks that are to be scaled. This is accomplished by checking the Log minimums and maximums check box for the relevant blocks, and accepting the Log Min, Max default value Use block params.

Global override with doubles is accomplished by configuring Doubles Override to All, and then running the simulation by selecting the Run button. The ideal and fixed-point plant output signals are then compared using the Plot System interface. The procedure for this simulation, and the simulation results are shown below.

The Plot System interface is shown below. This simulation plots both the fixed-point and ideal (double precision) signals for the plant output.

The ideal and fixed-point plant output signals are shown below. The ideal signal is produced by overriding the block output scaling.

Simulation 1: Initial Guess at Scaling

Simulation 3: Automatic Scaling