MATLAB: Do Relational Operator blocks contained within the Saturation Dynamic subsystem not appear in Simulink Coverage Analysis report

Question

I am using a Saturation Dynamic block in my model and I'm looking to perform coverage analysis for said model. When I run the Coverage Analysis and open up the resulting report, I observe that the 'Relational Operator' block that is contained within the 'Saturation Dynamic' block does not appear to be listed on the report under 'Saturation Dynamic subsystem' or anywhere else for that matter. 

Why does this happen?

Answer 1

When we ship blocks which are implemented as masked subsystems, under some circumstances we will explicitly disable coverage for certain "sub-blocks" under the mask. This might be done for various reasons, such as to avoid unsatisfiable objectives, ignore intermediate operations not pertinent in a customer's context, or just generally so that the coverage reported for the block better matches the conceptual behavior of the block.

In this case we have disabled coverage for the Relational Operator blocks under the mask of the Saturation Dynamic block. (You can confirm this by checking the 'DisableCoverage' parameter on each block)

Here, the Relational Operators feed directly into Switches. As such, condition coverage for the Relational Operator is no more informative than decision coverage for the Switch.

Furthermore, this makes coverage for the Saturation Dynamic block more consistent with coverage for the standard Saturation block. Both report two decision objectives -- one for exercising the upper boundary and another for exercising the lower boundary.