Lenze PLC Designer PLC Designer (R3-1) - Manual (Page 704)

L-force | PLC Designer
General Editors
702 DMS 4.1 EN 03/2011 TD29
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IL (Instruction List)
In IL a "branch" resp. "hanging coil" is represented by an appropriate order of
instructions. See in this context: Modifiers and operators in IL.
Contact
This is a LD element.
Each network in LD in its left part contains one or several contacts. Contacts are
represented by two parallel lines:
Contacts pass on condition "ON" (TRUE) or "OFF" (FALSE) from left to right.
A boolean variable is assigned to each contact. If this variable is TRUE, the condition is
passed from left to right and finally to a coil in the right part of the network, otherwise
the right connection receives the value FALSE.
Multiple contacts can be connected in series as well as in parallel. In case of two
parallel contacts only one of them must transmit the value TRUE in order to get the
parallel branch transmit the value TRUE. In case of contacts connected in series all
contacts must transmit the condition TRUE in order to get the last contact transmit the
TRUE condition.
So the contact arrangement corresponds to either an electric parallel or a series circuit.
A contact can also be negated, recognizable by the slash in the contact symbol:
A negated contact passes on the incoming condition (TRUE or FALSE) only if the
assigned boolean variable is FALSE. Notice that the ToolBox directly provides negated
contact elements.
A contact can be inserted in a LD network via one of the commands Insert Contact or
Insert Contact (right) resp. Insert Contact Parallel (above) or Insert Contact Parallel
(below) which by default are part of the FBD/LD/IL menu. Alternatively the element
can be inserted via drag&drop from the ToolBox or from another position within the
editor.
FBD, IL
If you are currently working in FBD or IL view, the command will not be available, but
contacts and coils inserted in a LD network will be represented by corresponding FBD
elements resp. IL instructions.