Lenze PLC Designer PLC Designer (R2-x) - Manual (Page 73)

L-force | PLC Designer
What is What in PLC Designer

DMS 3.2 EN 02/2011 TD29 71
Each network consists on the left side of a series of contacts which pass on from left to
right the condition "ON" or "OFF" which correspond to the Boolean values TRUE and
FALSE. To each contact belongs a Boolean variable. If this variable is TRUE, then the
condition is passed from left to right along the connecting line. Otherwise the right
connection receives the value OFF.
Example of a network in a Ladder Diagram made up of contacts and coils
Contact
Each network in LD consists on the left side of a network of contacts (contacts are
represented by two parallel lines: | |) which from left to right show the condition "On"
or "Off".
These conditions correspond to the Boolean values TRUE and FALSE. A Boolean
variable belongs to each contact. If this variable is TRUE, then the condition is passed
on by the connecting line from left to right, otherwise the right connection receives
the value "Out".
Contacts can be connected in parallel, then one of the parallel branches must transmit
the value "On" so that the parallel branch transmits the value "On"; or the contacts are
connected in series, then contacts must transmit the condition "On" so that the last
contact transmits the "On" condition. This therefore corresponds to an electric parallel
or series circuit.
A contact can also be negated, recognizable by the slash in the contact symbol: |/|.
Then the value of the line is transmitted if the variable is FALSE.