Power Rails

Vertical power rails are used in LD language for representing the limits of a rung.

The power rail on the left represents the TRUE value and initiates the rung state. The power rail on the right receives connections from the coils and has no influence on the execution of the program.

Power rails can also be used in FBD language. Only boolean objects can be connected to left and right power rails.

See also

Contacts   Coils