This function block is used for setting the system into a predefined state. All blocks of the actual flow are reset and lose its token if they have one. After this, all blocks that are connected by QP0-7 get a token.

Up to 8 tokens can be distributed by the outputs QP0-7. In this special case the outputs internally work like inputs. If a preset impulse is activated by the input Pres, then the signal processing of the target system will overwrite the actual state of tokens from the step blocks connected to the outputs.

This block works in two steps. At the point of the program cycle, at which the edge at Pres is detected, all STEPs of the net will be set back. At the following cycle the QP0-7 connected blocks get a token. Please pay attention to the block sequence here!

For general information about sequence function and its realization see introduction.


Name I/O Type(s) Function
Pres I BIT Activate preset
QP0 I/O BIT Blocks to preset
QP7 I/O BIT Blocks to preset


A sequence net can consist of one or more flows. All flows (even if they are uncoupled) of a structure block are part of the same flow net. Parts of a flow net can be placed in other hierarchical layers. For example, a macro block can be used to encapsulate parts of a flow.