Doc #: L-2600-1023 Page 25 Rev. 02
3.3.1.2 Cyclic
Cyclic inputs are derived from monitored events
that occur once each machine cycle when the
production process is functioning normally. An
example of a cyclic event is stripper plate
monitoring as shown in Figure 11. In normal
operation when the die closes, sensors on the
right and left sides of the stripper plate will turn
on; then, when the die opens again, the sensors
will turn off. When a slug is caught between the
stripper plate and the material, a fault condition
exists. Because of the slug, the right side of the
stripper plate did not come close enough to the
right sensor to turn it on. Since the sensor did
not turn on, a fault was detected and a stop
signal sent to the machine control.
When programming an input for cyclic mode,
the operator must enter crankshaft angles to
mark the “Window On” and “Window Off”
points for a timing window for the cyclic event.
The timing window setpoints should be
programmed so that the window covers the portion of the stroke in which the cyclic event should occur.
When a channel is
programmed to
monitor a cyclic
event, the event
must occur
sometime during the
timing window. In
addition, the event
must turn off
sometime during a
press stroke.
Acceptable and
unacceptable
conditions for cyclic
events are shown in
Figure 12. For all
of the acceptable
conditions the event
occurred sometime during the timing window. In addition, the event was off sometime during the
stroke. There are also three unacceptable conditions. The left unacceptable figure shows that the event
did not occur. The center unacceptable figure shows that event did occur, but did so outside the timing
window. The right unacceptable figure shows that the event did not turn off during an entire press
stroke. All three of these situations are fault conditions.
Upper Die
Lower Die
STRIPPER
PLATE
MATERIAL
SENSORS
Normal Operation
Upper Die
Lower Die
Fault
SLUG
Figure 11: Cyclic Input Example
0
180
90270
0
180
90270
0
180
90270
0
180
90270
0
180
90270
0
180
90270
0
180
90270
Acceptable
Unacceptable
Timing
Window
Sensor
Figure 12: Timing Window Examples for a Cyclic Input
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