Lenze PLC Designer PLC Designer (R3-1) - Manual (Page 706)

L-force | PLC Designer
General Editors
704 DMS 4.1 EN 03/2011 TD29
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Set/Reset in FBD/LD/IL
FBD and LD
A boolean output in FBD or correspondingly a LD coil can be "set" or "reset". To change
between the set states use the respective command Set/Reset from the context menu
when the output is selected. The output resp. coil will be marked by a S or a R.
Set: If value TRUE arrives at a set output resp. coil, this output/coil will get TRUE and
keep TRUE. This value cannot be overwritten at this position as long as the application
is running.
Reset: If value TRUE arrives at a reset output resp. coil, this output/coil will get FALSE
and keep FALSE. This value cannot be overwritten at this position as long as the
application is running.
Abb. 383 Set output in FBD, example
See also: Set and Reset Coils.
IL
In an instruction list the S and R operators are used to set or reset an operand.
Set/Reset Coil
Coils can also be defined as set or reset coils. One can recognize a set coil by the "S" in
the coil symbol: (S). A set coil will never overwrite the value TRUE in the appropriate
Boolean variable. That is, the variable once set to TRUE remains TRUE.
One can recognize a reset coil by the "R" in the coil symbol: (R). A reset coil will never
overwrite the value FALSE in the appropriate Boolean variable: the variable once set to
FALSE will remain FALSE.
In the LD editor Set coils and Reset coils can directly be inserted via drag&drop from
the ToolBox, category 'Ladder elements': , .
Abb. 384 Set coil, Reset coil, examples