Allen-Bradley Micro800 General Instructions Manual page 41

Chapter 3
Ladder Diagram (LD) elements
Change the type of coil
In the language editor, select the coil, then press the space bar until the new coil
type is available. Every time the space bar is pressed the type changes from direct,
to reverse, to set, to reset, to pulse rising edge, to pulse falling edge.
Direct Coil
A direct coil supports a Boolean output of a connection line Boolean state.
The associated variable is assigned with the Boolean state of the left connection.
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 an output or it must be user-defined.
Example: Direct coil
Reverse Coil
A reverse coil element supports a Boolean output according to the Boolean
negation of a connection line state.
The associated variable is assigned with the Boolean negation of the state of the
left connection. 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.
Rockwell Automation Publication 2080-RM001D-EN-E - February 2015 41