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

Basic definitions of a discrete block of library Blocks.Discrete. The output(s) will only change at events, but are not formally a discrete variable(s) in Modelica. The input(s) will be sampled, and can thus be continuous variable(s).

Important: If you connect several discrete blocks you should normally ensure that samplePeriod (and startTime) are exactly identical for all blocks, since otherwise the output from one block will be transformed into a continuous signal and sampled, which can cause a variable delay of up to one sample period leading to unexpected results.

Modelica 3.3 introduced synchronous operators that avoid the need to manually propagate samplePeriod to each block.