Rockwell Automation GMLC Reference Manual - Manual (Page 360)

Publication GMLC-5.2 - November 1999
On Watch 323
If you selected Wait for Tripped in the Watch Control block, do not use an
On Watch block, with Wait for Position Event selected. If you do, the
program waits for the same event twice.
The Wait for Position Event type requires no parameters, simply select the
desired physical or imaginary axis.
If other tasks are executing (multitasking), the task which contains this
block pauses, but the other tasks continue to execute. In this way, a Wait
for Position Event selection in one task does not pause execution of any
other tasks or hang the task dispatcher.
If Position Event
The If Position Event type evaluates a previously configured watch
position event for the selected axis, without pausing the program. The If
Position Event type executes only if a watch position event has previously
been set up for the selected axis, using Watch Control block with Arm
type and Watch Position class selected.
When the program executes, program flow branches to the top (true) node
if the event has occurred, or to the bottom (false) node if the event has not
occurred.
When multiple tasks are executing (multitasking), you can use an If
Position Event type in one task to evaluate a watch position event set up
in another task, even if Wait for Tripped is selected in the Watch Control
block. See Watch Control for more information on watch position events.
Wait for Registration
The Wait for Registration type pauses the program until the registration
event for the selected axis occurs.
The Wait for Registration Event type executes only if a registration event
has previously been set up for the selected axis, using a Watch Control
block with Arm type and Registration class selected.
If you selected Wait for Tripped in the Watch Control block, do not use an
On Watch block, with Wait for Registration selected. If you do, the
program waits for the same event twice.