Symbol: , in the editor

The element is available only in the LD editor.

A contact passes on the signal ‎TRUE‎ (ON) or ‎FALSE‎ (OFF) from left to right until the signal finally reaches a coil in the right side of the network. For this purpose, a Boolean variable containing the signal is assigned to the contact. To do this, replace the (‎???‎) placeholder above the contact with the name of a Boolean variable.

You can arrange multiple contacts both in series and in parallel. In the case of two parallel contacts, only one needs to get the value ‎TRUE‎ in order for ON to be passed on to the right. When contacts are connected in series, all of them have to get the value ‎TRUE‎ in order for ON to be passed on to the right by the last contact in the series. As a result, you can use LD to program electrical parallel and series connections.

A negated contact () passes the ‎TRUE‎ signal when the variable value is ‎FALSE‎. You can use the “FBD/LD/IL  Negation” command or insert a negated contact from the “Tools” view to negate an inserted contact.

When you place the mouse pointer over a contact with the left mouse button pressed and with a network selected, the “Convert to coil” button is displayed in the network. Now when you move the mouse pointer onto this button, still with the mouse button pressed, and then release the mouse button over this button, CODESYS converts the contact into a coil.

For more information, see: Command: ⮫ “Command: Insert Contact ”