For each block in the model that logs data, the GUI displays the block descriptive name, the minimum simulation value, the maximum simulation value, the maximum absolute error as a percentage of range, the data type, and the scaling. You can display a block's dialog box by double-clicking on the appropriate GUI entry.

The maximum absolute error as a percentage of range is a useful diagnostic parameter particularly for large models. A value of 100% or more typically indicates an overflow condition for that block although some other significant error such as saturation is also possible.

The Log Min/Max pull-down menu controls which blocks log data. All logs min/max data for all blocks, None doesn't log any min/max data, and Use block params logs min/max data for all blocks that have the Log minimums and maximums checkbox checked.

The Log Mode pull-down menu controls how the log file is updated when multiple simulations are run. Override log updates all logged values for each simulation run. Merge log keeps the highest and lowest logged values across multiple simulations.

Overriding the output data type with doubles is controlled with the Doubles Override pull-down menu. All overrides the output data type for all blocks, None doesn't override the output data type for any block, and Use block params overrides the output data type for blocks that have the Override with doubles checkbox checked.

Autoscale % Safety Margin sets the value for RangeFactor as a percent safety margin. For example, a RangeFactor of 1.20 is specified as 20. Before automatic scaling is performed, the simulation must be run to collect min/max data. For more information about RangeFactor, refer to page 8-3 of the Fixed-Point Blockset User's Guide.

The fixed-point GUI contains five buttons: Run, Stop, Autoscale, Plot, and Close. The Run button runs the model and updates the GUI display with the latest min/max values. The Stop button stops the simulation from running. The Autoscale button invokes the automatic scaling tool. The Plot button invokes the signal comparison tool, which displays any To Workspace, Outport, or Scope blocks found in the model. The Close button closes the fixed-point GUI.

The raw signal data is plotted with the Plot>Plot Signals button. Raw signal data is generated when the global override switch is off. Doubles are plotted with the Plot>Plot Doubles button. Doubles are generated when the global override switch is on. Both raw signal data and doubles can be plotted with the Plot>Plot Both button. Note that the doubles override does not overwrite the raw data.

Block path displays the path for each selected block.

Example
The Fixed-Point GUI block is included with all demos. To learn how to use the GUI, select the Automatic Scaling in Feedback Control demo, and follow the steps outlined in "Simulation Results" in Chapter 6 of the Fixed-Point Blockset User's Guide.