How to use parameter callback to parameterize mask workspace?

I am struggling to do what I thought would be super simple. I would like to parameterize a subsystem by using the mask work space.

As a super simple example, let's say I have a mask with a single input parameter -- frequency (f) in Hz. In the mask workspace, I would then like to have a derived variable for period -- T = 1/f that I can use throughout my blocks. T should then update anytime f is updated. Of course I could just directly plug in 1/f everywhere I would use T, but this isn't my design intent and doesn't always work when the expression for the derived variable is more complicated.

This seems like a perfect use case for parameter callbacks inside of a mask, but I cannot get it to work, and can't find any examples of anyone doing this online.

Here's my super simple subsystem:

Here's the mask setup with a single parameter:

And here's my attempt at creating a parameter callback:

What am I doing wrong and how do I accomplish this? I'm super surprised there isn't any examples of this in the documentation as parameterizeing a model like this seems like a fairly common use case.

Thanks,

Nick

Answer 1

[Paul]

What happens if you just enter

T = 1/f;

in the Initialization section and leave the f_callback blank, or delete it altogether?