{"id":3878,"date":"2014-07-03T13:43:39","date_gmt":"2014-07-03T18:43:39","guid":{"rendered":"https:\/\/blogs.mathworks.com\/seth\/?p=3878"},"modified":"2017-01-20T17:24:16","modified_gmt":"2017-01-20T22:24:16","slug":"what-about-a-resettable-subsystem","status":"publish","type":"post","link":"https:\/\/blogs.mathworks.com\/simulink\/2014\/07\/03\/what-about-a-resettable-subsystem\/","title":{"rendered":"What about a Resettable Subsystem?"},"content":{"rendered":"

UPDATE: Since R2015a, a resettable block is now shipping with Simulink... yeah!<\/strong><\/em><\/p>\r\n\r\n

https:\/\/www.mathworks.com\/help\/simulink\/ug\/reset-block-states-in-a-subsystem.html<\/a><\/p>\r\n\r\n

------------------- original post --------------------<\/p>\r\n\r\n

I often write about new features in Simulink. Today I take a different route and write about a feature that I would like to see in Simulink.<\/p>\r\n\r\n

Please leave a comment below if you have similar needs and use cases.<\/p>\r\n\r\n

My Need<\/strong><\/p>\r\n\r\n\r\n

In various applications I work on, I often end up needing to reset the states of multiple blocks at the same time. Some blocks like Integrator<\/a> and Delay<\/a> have reset ports which I can use for this purpose. However other blocks like State-Space<\/a>, Transfer Function<\/a> or Unit Delay<\/a> do not.<\/p>\r\n\r\n

Blocks with Reset Ports<\/strong><\/p>\r\n\r\n

If blocks have reset ports, I can arrange my diagram to reset all those blocks at the same time:<\/p>\r\n\r\n

\"Resetting<\/p>\r\n\r\n

This gives me the behavior I need, but if I have many blocks that need to be reset, this is a lot of routing. Also, there are multiple blocks that have states, but do not have an optional reset port.<\/p>\r\n\r\n

Enabled Subsystem<\/strong><\/p>\r\n\r\n

What I am really dreaming of is a subsystem with a control port like the Enabled Subsystem<\/a>, without the need to disable for one step to reset the states. With an Enabled Subsystem the control signal resets the states when it is re-enabled.<\/p>\r\n\r\n

\"Enabled<\/p>\r\n\r\n

When simulating the model, we can see that this is not ideal because the system is disabled during one step:<\/p>\r\n\r\n

\"Enabled<\/p>\r\n\r\n

Function-Call subsystem and Stateflow<\/strong><\/p>\r\n\r\n

Using Stateflow it is possible to reset the states in a subsystem without disabling it for one step.<\/p>\r\n\r\n

To make that happen, we need to place the blocks inside a Function-Call Subsystem<\/a>. We can then drive the subsystem with a Stateflow Chart<\/a>. In the chart, bind an output event to a state<\/a> and exit this state to trigger the reset of the states in the Function-Call Subsystem:<\/p>\r\n\r\n

\"Function-Call<\/p>\r\n\r\n

Note, this solution will not work for blocks with continuous states like Transfer Function, State-Space, etc.<\/p>\r\n\r\n

Now it's your turn<\/strong><\/p>\r\n\r\n

Do you see the need in your applications for a subsystem where the states of all the blocks inside would reset from a rising edge on a control port? Let us know by leaving a comment here<\/a>.<\/p>\r\n\r\n\r\n","protected":false},"excerpt":{"rendered":"

<\/div>\r\n

In various applications I work on, I often end up needing to reset the states of multiple blocks at the same time. Some blocks like Integrator<\/a> and Delay<\/a> have reset ports which I can use for this purpose. However other blocks like State-Space<\/a>, Transfer Function<\/a> or Unit Delay<\/a> do not.... read more >><\/a><\/p>","protected":false},"author":41,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[24],"tags":[390,391],"_links":{"self":[{"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/posts\/3878"}],"collection":[{"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/users\/41"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/comments?post=3878"}],"version-history":[{"count":18,"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/posts\/3878\/revisions"}],"predecessor-version":[{"id":6320,"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/posts\/3878\/revisions\/6320"}],"wp:attachment":[{"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/media?parent=3878"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/categories?post=3878"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/tags?post=3878"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}