S-function works in normal mode but doesn't in external mode

I'm trying to implement a simple s function builder ode solver for a rlc circuit, it is suposed to return the value of the capacitor voltage.

While it works fine in normal mode.

when deployed to TI TMS320F28379D the response remais at 0, it simply doesn't work. It builds and deploys fine.

Any help is aprecciated.

Answer 1

[Venkatesh Chilapur]

Hi,

When deploying the model on target we configure it for Fixed step disctere solver as the controller runs in discrete amount of time. It also depends on the step time your model is configured to run. If the model is configured to run fast, then the external mode may not work.

HTH,

Venkatesh C

[Arthur Nascimento]

Hello, thanks for the answer, this is how the solver is set up:

I also tried some higher values fo the fixed step time, same problem.

Answer 2

[Venkatesh Chilapur]

Can you do a crtl+j and send the snap of Sample Time Legend that pop's up as below.

[Arthur Nascimento]

The model along with the s function files are attached, something tells me that the external mode isn't calling the "update" part of the code.

Answer 3

[Venkatesh Chilapur]

Hi,

Could run the model in external mode and could recieve only zero.

I have not debugged the S-Function, but I can recommend to start with simple model and see if that works.

I could see a sample time of 0.2sec in your attached model. You may try to run at this rate.

Regards,

Venkatesh C

[Arthur Nascimento]

Hello, I have found the problem to be the use of the simStruct functions. I was using it to get the sample time value. While it works fine in normal mode, it doesn't seem to work in external mode. I need to set the sample time in simulink configs and set the same sample time in the code for the solver to run properly. Thanks for the help anyway!!