Rate Limiter
Limit rate of change of signal
Libraries:
Simulink /
Discontinuities
Description
The Rate Limiter block limits the first derivative of the signal passing through it. The output changes no faster than the specified limit. The derivative is calculated using this equation:
$$rate=\frac{u(i)y(i1)}{t(i)t(i1)}$$
where u(i) and t(i) are the current block input and time, and y(i1) and t(i1)) are the output and time at the previous step. The output is determined by comparing rate to the Rising slew rate and Falling slew rate parameters:
If rate is greater than the Rising slew rate parameter (R), the output is calculated as
$$y(i)=\Delta t\cdot R+y(i1).$$
If rate is less than the Falling slew rate parameter (F), the output is calculated as
$$y(i)=\Delta t\cdot F+y(i1).$$
If rate is between the bounds of R and F, the change in output is equal to the change in input:
$$y(i)=u(i)$$
When the block is running in continuous mode (for example, Sample time
mode is inherited
and Sample
time of the driving block is zero), the Initial
condition is ignored. The block output at t = 0
is
equal to the initial input:
$$y(0)=u(0)$$
When the block is running in discrete mode (for example, Sample time
mode is inherited
and Sample
time of the driving block is nonzero), the Initial
condition is preserved:
$$y(1)=Ic$$
where Ic is the initial condition. The block output at t =
0
is calculated as if rate is outside the bounds of
R and F. For t = 0
,
rate is calculated as follows:
$$rate=\frac{u(0)y(1)}{sample\text{\hspace{0.17em}}time}$$
Limitations
You cannot use a Rate Limiter block inside a Triggered Subsystem. Use the Rate Limiter Dynamic block instead.
Ports
Input
Output
Parameters
Block Characteristics
Data Types 

Direct Feedthrough 

Multidimensional Signals 

VariableSize Signals 

ZeroCrossing Detection 

Extended Capabilities
Version History
Introduced before R2006a