Equipments (Devices) > SCA06 > Ladder > Contact

Falling edge transition contact.

Ladder Representation

Block Structure

Variable Type	Name	Data Type	Description
VAR_INPUT	I1	BOOL	Block control input
VAR	NTSCONTACT_INST_0	NTSCONTACT	Instance of access to block structure

Operation

At the instant the variable I1 transitions from TRUE to FALSE (falling edge or negative edge transition), B receives the value of A for a scan cycle.

At all other times, B receives the FALSE value.

NOTE!

Watch out for series and parallel associations of contacts. Refer to section Contact Logic for further information.

Diagram

NTSCONTACT_diagram

Block Flowchart

NTSCONTACT_flowchart

Example in Ladder

NTSCONTACT_example

The above example resets the digital output DO1 if the SHIFT key is pressed or a positive pulse on the digital input DI2 is given.

Example in ST

The example below displays the instructions for applying the example above in the ST language.

VAR

NTSCONTACT_INST_0 : FB_NTSCONTACT;

END_VAR

NTSCONTACT_INST_0(EN:=TRUE, BIT:=DI2);

DO1 := FB_RESETCOIL(EN:=(KEY_SHIFT OR NTSCONTACT_INST_0.Q));