I am trying to evaluate whether I should control a system in simulink using sampled data system or discrete time system.

The discrete model is as follows: enter image description here

The sampled time system is as follows enter image description here

What is the functional difference between these two and which approach is preferred in realistic modelling and control?

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    $\begingroup$ the ZOH on the left has no meaning. does the A/D converter live there? the ZOH on the right probably means where the D/A is. and that ZOH does have meaning since the loop feedback path is evidently an analog line. $\endgroup$ – robert bristow-johnson Apr 6 '15 at 18:57

The first one is a purely discrete model. You need to select a discrete solver in the simulation options to accurately simulate this system. The second system however is actually continuous because of the holders, so you need a continuous time solver.

The preferred approach depends on what your system is. If you have a discrete model to work on, you should prefer the first one. If you have an actual physical system that you want to control with a microcontroller, you should prefer the second one.


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