This function block realizes a transition, i.e. a condition to step forward a sequence control. It is always located between steps.

A transition has the inputs SB, TI and the output TO. SB set the condition of a transition block for passing a token. A HIGH signal allows the passing of a token coming from a step connected to TI down to a step connected to the output TO.

If no signal is connected to input SB, the transition always allows the passing of tokens.

TI and TO have to be connected. Otherwise the download to the target system will be disrupted with an error message.

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


Name I/O Type(s) Function
TI I TOTRANS Sequence input
SB I BIT Passing condition
TO O TOSTEP Sequence output


If the transition is not connected properly, the symbol will be depicted red in the run mode.