Attention

IronPLC can only run very simple programs. The steps described are accurate but many language features are not yet supported.

Contacts

Contacts are input elements in ladder diagrams that read the state of a boolean variable. Power flows through a contact when its condition is met.

IEC 61131-3

Section 3.2

Support

Not yet supported

Contact Types

Type

Symbol

Description

Normally open

--| |--

Passes power when the associated variable is TRUE

Normally closed

--|/|--

Passes power when the associated variable is FALSE

Positive transition

--|P|--

Passes power on rising edge (FALSE to TRUE)

Negative transition

--|N|--

Passes power on falling edge (TRUE to FALSE)

Description

A normally open contact is equivalent to reading a boolean variable directly. A normally closed contact is equivalent to applying NOT to the variable.

See Also