Rockwell Automation GMLC Reference Manual - Manual (Page 331)

Publication GMLC-5.2 - November 1999
294 I/O and Event Blocks
Command position is a more stable reference for camming, because it
does not incorporate any associated following error or external position
disturbances. When you use the command position, the selected axis must
be commanded to move in order to cause any output cam transitions. See
the Installation and Setup manual for your motion controller for more
information on command position.
Defining the Window
The position window, within which the selected discrete output is on, is
defined by the start of window and end of window values, as shown
below.
For linear axes, both values may be positive (as shown above) or
negative, or may be of different signs. However, the start of window value
should be less than the end of window value, otherwise the output is never
turned on.
For rotary axes, both values must be less than the value of the conversion
constant divided by the unwind constant (as set in Configure Axis Use
Feedback dialog box). The start of window value may be greater than the
end of window value to allow output cams which cross the unwind point
of the axis.
ON
OFF
Output Cam
Position Window
Axis Position
Start of
Window End of
Window