Attention

IronPLC implements many parts of the IEC 61131-3 standard and is working toward full Structured Text support. Key features still missing include arrays and structures. Try it out in the IronPLC Playground.

Branches

Branches create parallel and series connections in ladder diagrams, allowing multiple logic paths within a single rung.

IEC 61131-3	Section 3.2
Support	Not yet supported

Description

Parallel branches (OR logic) connect contacts side by side. Power flows if any branch is TRUE:

|    input_a                         |
|---| |---+---( output )---|
|         |                          |
|    input_b                         |
|---| |---+
|                                    |

This is equivalent to output := input_a OR input_b in Structured Text.

Series connections (AND logic) place contacts end to end. Power flows only if all contacts are TRUE:

|    input_a     input_b     output  |
|---| |-------| |---( )---|
|                                    |

This is equivalent to output := input_a AND input_b in Structured Text.

See Also

• Rungs — logic lines

• Contacts — input elements

• Coils — output elements