Allen-Bradley Micro800 General Instructions Manual page 42

Chapter 3
Ladder Diagram (LD) elements
42
Example: Reverse Coil
Pulse Falling Edge Coil
Pulse falling edge (or negative) coils support a Boolean output of a connection line
Boolean state.
The associated variable is set to TRUE when the Boolean state of the left
connection falls from TRUE to FALSE. The output variable resets to FALSE in
all other cases. The state of the left connection is propagated into the right
connection. The right connection must be connected to the right vertical power
rail (unless you have parallel coils, where only the upper coil must be connected to
the right vertical power rail).
The associated Boolean variable must be output or it must be user-defined.
Example: Pulse Falling Edge Coil
Pulse Rising Edge Coil
Pulse rising edge (or positive) coils support a Boolean output of a connection line
Boolean state.
Rockwell Automation Publication 2080-RM001D-EN-E - February 2015