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 output signal may have an upper and lower limit. 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 behaviour of the external reset input. The values rising,
falling and either cause 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
to a positive value, a falling edge is detected when the signal changes from a positive value to
. If the value level is chosen, the output signal keeps the initial value while the reset input is not
.
- 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. This parameter may be either a scalar or a vector corresponding to the implicit width of the component. If the Initial condition source parameter is set to external, this parameter is ignored.
- 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.
- Upper saturation limit
- An upper limit for the output signal. If the value is inf the output signal is unlimited.
- Lower saturation limit
- A lower limit for the output signal. If the value is -inf the output signal is unlimited.
Probe Signal
- 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, if the output signal is fed back to create the reset signal or an initial value, PLECS will flag an algebraic loop error. This can be avoided by using the state port instead.