Check Dynamic Lower Bound (Simulink Reference)

Check that one signal is always less than another signal.

Library

Model Verification

Description

The Check Dynamic Lower Bound block checks that the amplitude of a test signal is less than the amplitude of a reference signal at the current time step. The test signal is the signal connected to the input labeled sig. If the verification condition is true, the block does nothing. If not, the block halts the simulation, by default, and displays an error message.

The Check Dynamic Lower Bound block and its companion blocks in the Model Verification library are intended to facilitate creation of self-validating models. For example, you can use model verification blocks to test that signals do not exceed specified limits during simulation. When you are satisfied that a model is correct, you can turn error-checking off by disabling the verification blocks. You do not have to physically remove them from the model. If you need to modify a model, you can temporarily turn the verification blocks back on to ensure that your changes do not break the model.

Data Type Support

The Check Dynamic Lower Bound block accepts input signals of any dimensions and any built-in data type except int64 and uint64. The test and the reference signals must have the same dimensions and data type. If the inputs are nonscalar, the block checks each element of the input test signal to the corresponding elements of the reference signal.

Parameters and Dialog Box

Enable Assertion: Unchecking this option disables the Check Dynamic Lower Bound block, that is, causes the model to behave as if the block did not exist. The Advanced Pane of the Simulation Parameters dialog box allows you to enable or disable all model verification blocks, including Check Dynamic Lower Bound blocks, in a model regardless of the setting of this option.
Simulation callback when assertion fails: An M-expression to be evaluated when the assertion fails.
Stop simulation when assertion fails: If checked, this option causes the Check Dynamic Lower Bound block to halt the simulation when the block's input is zero and display an error message in Simulink's Simulation Diagnostics viewer. Otherwise, the block displays a warning message in the MATLAB command window and continues the simulation.
Output Assertion Signal: If checked, this option causes the block to output a Boolean signal that is true (1) at each time step if the assertion succeeds and false (0) if the assertion fails. The data type of the output signal is boolean if you have selected the Boolean logic signals option on the Advanced pane of Simulink's Simulation Parameters dialog box. Otherwise the data type of the output signal is double.
Select Icon Type: Type of icon used to display this block in a block diagram: either graphic or text. The graphic option displays a graphical representation of the assertion condition on the icon. The text option displays a mathematical expression that represents the assertion condition. If the icon is too small to display the expression, the text icon displays an exclamation point. To see the expression, enlarge the icon.

Characteristics

Direct Feedthrough
No

Sample Time
Inherited from driving block

Scalar Expansion
No

Dimensionalized
Yes

Zero Crossing
No

Direct Feedthrough	No
Sample Time	Inherited from driving block
Scalar Expansion	No
Dimensionalized	Yes
Zero Crossing	No

Check Dynamic Gap Check Dynamic Range