Tips to convert a subsystem into Requirement Table block

Task: I am trying to convert following subsystem block into requirement block, so that I can further analyze my model function using requirement analysis.

Actions taken: I have tried to make the requirement table as follows:

Here, value is a local data, Input1 and Input2 are 2 inputs and Output1 is the Output.

Issue: I am unable to simulate the requirement table if I convert the subsystem into a requirement table. The error message is "Local data 'value' is not supported as an input for 'prev' or 'duration' in requirement cells". Can you please suggest me if there is any other way I can convert it into requirement table?

Answer 1

[Josh Kahn]

Hey @Shubham,

Local data is not stored between timesteps so there is no prev(value). If you want to use a variable that persists, I recommend switching it to Parameter in which case you can define it in the MATLAB workspace.

Ideally, value would be input data in which case you can feed the same source into your subsystem and your requirements table block and evaluate the expected output.

For more information, see Define Data in Requirements Table Blocks:

https://www.mathworks.com/help/slrequirements/ug/modify-requirements-table-block-data.html

Hope this helps,

Josh

[Shubham]

Thank you for your response. I knew that local data don't have prev(value), since it is evaluated at every time step and removed before going to the next step. However, I was curious if there was a way I can define "intermediate output" which is treated similar to Output Data but doesn't show on the Outport of the requirement block.