Integrator
Purpose
Integrate input signal with respect to time
Library
Control / Continuous
Description
The Integrator block outputs the integral of its input signal at the current time step. The integrator state may saturate at an upper and lower limit, or it can be wrapped between two limits. It can be reset to its initial value by an external trigger signal. The initial value may be provided either via a parameter or via an input signal.
Interaction with the Solver
- Simulation with the Continuous State-Space Method
When simulated with the continuous method, the input signal is simply passed on to the solver for integration.
- Simulation with the Discrete State-Space Method
When simulated with the discrete method, the input signal is integrated within PLECS using the Forward Euler method.
Parameters
- External reset
The behavior of the external reset input. The values
rising,fallingandeithercause a reset of the integrator on the rising, falling or both edges of the reset signal. A rising edge is detected when the signal changes from \(0\) to a positive value, a falling edge is detected when the signal changes from a positive value to \(0\). If the valuelevelis chosen, the output signal keeps the initial value while the reset input is not \(0\).- Initial condition source
Specifies whether the initial condition is provided via the Initial condition parameter (
internal) or via an input signal (external).- Initial condition
The initial condition of the integrator. The value may be a scalar or a vector corresponding to the implicit width of the component. This parameter is shown only if the Initial condition source parameter is set to
internal.- Show state port
Specifies whether to show an additional state output port. The state port is updated at a slightly different point in the block execution order (i.e. before the reset and initial condition inputs are evaluated) and may therefore be used to calculate an input signal for the external reset input or the initial condition input.
- Enable wrapping
When set to
on, the integrator state is wrapped between the Upper wrapping limit and Lower wrapping limit parameters. The default isoff. Note that wrapping is mutually exclusive with saturation.- Upper saturation limit
An upper limit for the integrator state. If the value is
inf, the state is unlimited. This parameter is visible only if Enable wrapping is set tooff.- Lower saturation limit
A lower limit for the integrator state. If the value is
-inf, the state is unlimited. This parameter is visible only if Enable wrapping is set tooff.- Upper wrapping limit
The upper wrapping limit for the integrator state. When the state exceeds the upper limit, it is wrapped to the lower limit. This parameter is visible only if Enable wrapping is set to
on.- Lower wrapping limit
The lower wrapping limit for the integrator state. When the state exceeds the lower limit, it is wrapped to the upper limit. This parameter is visible only if Enable wrapping is set to
on.
Probe Signals
- State
The internal state of the integrator.
Note
Both the external reset input and the initial condition input have direct feedthrough on the output signal. Therefore, feeding back the output signal to create the reset signal or an initial value will create an algebraic loop. This can be avoided by using the state port instead.