Contacts

Contacts are graphic components of Ladder Diagram (LD) diagrams. Depending on the type of contact, it represents the value or function of an input or internal variable.
Contact types available from the LD stencil are:
  • Direct Contact
  • Reverse Contact
  • Pulse Rising Edge Contact
  • Pulse Falling Edge Contact
Change the type of a contact at any time after insertion.
When inserting contacts in program organization units (POUs), assign variables using the Variable Selector. Names of assigned variables display above the contact elements within POUs. Replace existing variables by double-clicking the variable names to access the Variable Selector or by single-clicking variable names to select from drop-down combo boxes containing the global and local variables. Also single-click existing variables, then type literal values in the text boxes provided. When inserting literal values beginning with a letter or an underscore, enclose the variable name in single quotes as follows: 'abc'.
Select a variable from the drop-down combo-box:
Type a literal value in the text box:
ldr_cl1
ldr_cl2
When selecting items like local variables, controller variables, system variables, and defined words from the drop-down combo box, type characters in the text box to focus on the possible items.
While dragging contacts from either the toolbox or within a diagram, the language editor displays the possible drop points. Drop points display as plus signs in a black circle. For elements, the possible drop points display on the rung.
Drop points on a rung while dragging elements over the rung
ldr_dpct
Task
Procedure
Insert a contact
  1. From the Toolbox, drag the desired contact type into the language container and place it on the rung where a drop point appears.
    The Variable Selector appears.
  2. In the Variable Selector, select the required variable, then click
    OK
    .
    The contact and its associated variable name appear on the rung.
Insert a parallel contact
  1. From the Toolbox, drag the branch element on the existing contact in the language container.
  2. From the Toolbox, drag the desired contact type on the branch.
    The Variable Selector appears.
  3. In the Variable Selector, select the required variable, then click
    OK
    .
    The contact and its associated variable name appear on the branch.
Drag a contact
  • To reposition a contact within the diagram, select the contact while holding down the left mouse button, then drag the contact to the required location on a rung where a drop point is displayed.
Change the type of a contact
  • In the language container, select the contact, then press the space bar.
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