Use fixed-step solver ode1 to execute variable sample time Zero Order Hold

I got an error "Cannot compile diagram, because it contains variable sample times or S-functions and is using a fixed-step solver." when running a model which contains a variable sample time Zero Order Hold block written by S-function.

As fixed-step solver is a must for my simulation, I tried to solve this problem by(e.g):

1.set the fixed-step size as 1e-6 s;

2.keep the sample time of ZOH as n*(1e-6s), where n is a integer varies from 20 to 50;

I thought this may fix the problem as the sample time is integer multiple fixed-step size and the solver can solve this.

However, it does not work.

My question is, is there a way to implement a ZOH with variable sample time and use the fixed-step solver?

[Darshan Ramakant Bhat]

Will the following answer link help you?

https://www.mathworks.com/matlabcentral/answers/98293-is-there-a-fixed-step-ordinary-differential-equation-ode-solver-in-matlab-8-0-r2012b?s_tid=answers_rc1-2_p2_MLT

Answer 1

[Archit Dhanani]

Simulink supports variable sample times for variable-step solvers only. You can read more about this in the page:

https://www.mathworks.com/help/simulink/ug/types-of-sample-time.html#brrdmmw-11

Could you try to use controllable sample times instead?