MATLAB: Trouble with Enable subsystem.

Question

Hello Guys, I am implementing a Simulink structure which uses Enable Subsystems. Based on a certain condition either the value of 1 of -1 goes into the Enabled input. When the input is -1, the subsystem is disabled. However, as soon as the input is 1, the Enable is is always set at 1 and it then holds this value and hence the subsystem always computes. I don't want this to happen. I want the Enabled subsystem not to run when the value is -1. How do I do this? Here are some pictures to clarify.

This is the switch I'm using to trigger:

This is the output of the switch:

Here is the output of the Enable:

I don't understand why its always 1.

Any suggestions? Thanks, Prakash

Answer 1

Hi Prakash,

no, the enable system does not compute when the enable signal is not positive. But the outport hold the last computed value. Go into the enable subsystem, open the outport and switch "Output when disabled" from the default "held" to "reset".

Titus