If there is an output port, the second zero crossing is Zero crossing to detect when the input signal hit the threshold If there is no output port, there is only one One, to detect when the input signal has a discontinuity in Provides the capability to detect zero crossings. One, If an Enable port is inside of a Subsystem block, it Zone is exited (the input signal minus the upper Signal minus the lower limit), and one to detect when the dead Two, one to detect when the dead zone is entered (the input One, to detect when the signal equals zero. One to detect when the lower threshold is Two, one to detect when the upper threshold is engaged, and One, to detect when the input signal crosses zero in either The second, the solver detects sign change and therefore detects the zero-crossing Integrator steps over the event because the sign has not changed between time steps. The following figure shows a signal that crosses zero. The solver steps over the crossing without detecting it. Step, but the values at the beginning and end of the step do not indicate a sign change, However, if a zero crossing occurs within a time
A signĬhange indicates that a zero crossing has occurred, and the zero-crossing algorithm This is possible because the zero-crossing detection techniqueĬhecks to see if the value of a signal has changed sign after a major time step.
It is also possible for the solver to entirely miss zero crossings if the solver error The bounce and double-bounce models, in Simulation of a Bouncing Ball and Double Bouncing Ball: Use of Adaptive Zero-Crossing Location show that high-frequency fluctuationsĪbout a discontinuity (chattering) can cause a simulation to prematurely halt.
How the Simulator Can Miss Zero-Crossing Events
Simulation time, and is seldom necessary when using the adaptive However, reducing the step size can increase The solver takes steps small enough to resolve the zeroĬrossing. A consequence is that your model no longerīenefits from the increased accuracy that zero-crossingĪdjusting the order of the numerical differentiation This prevents zero crossings from being detected anywhere All other blocks continue to benefitįrom the increased accuracy that zero-crossing detectionĭisable zero-crossing detection for the entire Specific block from stopping the simulation because of excessiveĬonsecutive zero crossings. Locally disabling zero-crossing detection prevents a Have the option of specifying both the Timeĭisable zero-crossing detection for a specific Threshold, which improves accuracy and reduces the number ofĬonsecutive zero crossings detected. This algorithm dynamically adjusts the zero-crossing This can reduce simulation time and eliminate anĮxcessive number of consecutive zero-crossing errors. The solver requires less time to precisely locate the zeroĬrossing. Value of the Signal threshold option on the This may give your model enough time to resolve the zero Increase the value of the Number of consecutive Number of consecutive zero-crossings : 500īlock path : 'example_bounce_two_integrators/Position'Īlthough you can increase this limit by adjusting the Model Configuration Parameters > Solver > Number of consecutive zero crossings parameter, making that change still does not allow the simulation to go on for 25 s.Ĭhange the Solver details > Zero-crossing options > Algorithm parameter in the Solver pane of the Model configuration parameters to Adaptive and simulate the model again for 25 s. Number of consecutive zero-crossings : 1000īlock path : 'example_bounce_two_integrators/Compare To Zero/Compare' Simulink will stop the simulation of model 'example_bounce_two_integrators' because the 2 zero crossing signal(s) identified below caused 1000 consecutive zero crossing events in time interval between 20.357636989536076 and 20.357636990631594.