Writing S-Functions

mdlZeroCrossings

Update zero-crossing vector.

Syntax

void mdlZeroCrossings(SimStruct *S)

Arguments
S
   Simstruct representing an S-function block.

Description

An S-function needs to provide this optional method only if it does zero-crossing detection. This method should update the S-function's zero-crossing vector, using ssGetNonsampleZCs.

You can use the optional mdlZeroCrossings routine, when your S-function has registered the CONTINUOUS_SAMPLE_TIME and has nonsampled zero crossings (ssGetNumNonsampledZCs(S) > 0). The mdlZeroCrossings routine is used to provide Simulink with signals that are to be tracked for zero crossings. These are typically:

• Continuous signals entering the S-function
• Internally generated signals that cross zero when a discontinuity would normally occur in mdlOutputs

Thus, the zero crossing signals are used to locate the discontinuities and end the current time step at the point of the zero crossing. To provide Simulink with zero crossing signal(s), mdlZeroCrossings updates the ssGetNonsampleZCs(S) vector.

Example

See matlabroot/simulink/src/sfun_zc.c.

Languages

C

See Also

mdlInitializeSizes, ssGetNonsampleZCs

mdlUpdate

SimStruct Functions