Contacts and coils

In LD and FBD, contacts, coils, jumps, returns, and Boolean input and output contacts can be negated. Negated jumps, returns or input and output contacts are represented by a small circle. Negated contacts and coils are represented by a slash. Double-click on the contact or coil to negate them or follow the procedure below to negate a Boolean input.

The input of contacts and coils may be triggered by a rising or falling edge. ‘N’ (negative) indicates a falling edge, 'P' (positive) a rising edge. Double-click on the contact or coil to set the edge detection.

While inserting new elements (before the new element is placed in the network), <Shift> toggles between the following behaviour of the element:

Coils keep their TRUE state when their input has been configured as Set (S). They remain set until reset by a Reset (R) coil. Reset coils keep their FALSE state until reset by a set coil. Double-click on the coil to set or reset its input.

Example for negating an input

1. Insert instruction with Boolean input or output

2. Check that the placement mode is active

3. Double-click on an input pin (1)

   

   The Signal configuration dialog opens.

4. Select Negation

5. OK

   The negated contact (2) is indicated by a small circle.