Simulink S-function builder reading inputs

Hello all,

I have just started to learn how to implement the S-functions via

the Simulink S-function builder. I have been attempting to model

a discrete system with two 1-D inputs (act and ref) and one

1-D output (u). My C language code for the outputs calculation is

following

double ref;

double act;

double e;

e = ref - act;

u[0] = e;

The building process is successful but whenever I start the simulation

process there is zero at the S-function block output despite the fact

that the ref input is non-zero.

I have also tried a different version of C code:

double ref;

double act;

double e;

e = ref[0] - act[0];

u[0] = e;

But in that case I was not able to build the code.

Can anybody tell me what I have been doing wrong?

Answer 1

[Fangjun Jiang]

"u" is usually referred as inputs, "y" is usually referred as outputs.

You need to go through the S-Function Builder Dialog Box to fill the info and copy&paste your C code.

S-Function Builder Dialog Box