PID sampling time in modelingtoolkit

Specific Domains Modelling & Simulations
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Hi. I’ve built a modelingtoolkit model to simulate my process system. It uses PID controllers, the issue is that the control system has a sampling time of 1s. This has a huge effect on the parameters for the controller and the level of control they can have. How would you simulate this in modelingtoolkit?

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Not trivial, because hybrid systems (combining continuous and discrete elements) are not yet well-supported.

I would use the integrator interface and implement the controller in Julia (without MTK) and only your process in MTK. For the controller, you could, for example, use GitHub - JuliaControl/DiscretePIDs.jl: Discrete-time PID controllers in Julia .

But there might be better ways to do this.

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Thanks, that’s what I was thinking, but it gets quite messy with multiple controllers etc

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Example for a dual-loop PID controller with linearization: SimpleKiteControllers.jl/src/parking_controller.jl at main · OpenSourceAWE/SimpleKiteControllers.jl · GitHub

I don’t find it messy, but your mileage might vary.