This information is part of the Modelica Standard Library maintained by the Modelica Association.

This block asserts that the Boolean input u is true. If u is false, the simulation will either abort with an error (if assertionLevel is set to error), or issue a warning and continue (if assertionLevel is set to warning). The message will be reported in either case. For further information, refer to the documentation of ModelicaReference.Operators.'assert()' – an operator which this block is based on.

Typically, this block is used by connecting a (possibly) time varying outside condition and the input u to abort the simulation if the condition fails.