LINK Systems OmniLink II Press Automation Control - Manual (Page 123)

August 30, 2002 Manual Version 1.0 6.18
part is totally out of the die area.
The Two Part Detector Edge input type
functions much like the One Part Detector
Edge type, the difference being that two
parts must be sensed. The first part must
be sensed in the timing window. The
leading edge of the second part must be
sensed in the timing window. With Two
Part Detector Edge, it is not required that
the second part completely passes the
sensor by the end of the window. There
must be a separation time between the
parts. The first part must completely exit
the sensor before the second part enters
the sensor. The timing for Two Part
Detector Edge is shown in Figure 6.16.
The sensor being used to verify part
detection can be Normally Off or Normally On.
The sensor will switch from its normal state
when the part is being detected. When a
Normally Off sensor is being used to sense part
out; the sensor will be Off when the part is not in
the sensor, and will be On when the part is in the
sensor. When a Normally On sensor is being
used to sense part out; the sensor will be On
when the part is not in the sensor, and will be
Off when the part is in the sensor.
Section 6.5.7 Two Part Detection Pass
The Two Part Detector Pass channel logic type is used to monitor ejection for two parts detected by a
single sensor. In addition, the second part must be completely past the sensor by the end of the timing
window. The channel logic looks for two parts to be sensed during the timing window, and also looks
for the second part to be past the sensor at the end of the timing window. An example of Two Part
Detector Pass is shown in Figure 6.17. This example shows two exiting parts sliding down a chute.
When the sensor first detects the leading edge of the second part, the trailing edge of the part is still in
the die area. Detection of the leading edge of this part does not insure that the second part is totally out
of the die area. The only way to insure that the second part is completely out of the die is to require that
it be completely past the sensor by the end of the timing window.
TRANSMITTER RECEIVER
TWO SMALL PARTS DETECTED BY OPTICAL PART DETECTOR
SEPRATION
TIME
Figure 6.15 Two Part Detector Edge
0
180
90
Part Can Exit
After Timing
Window
Parts Must Enter
In Timing
Window
Two Part-Edge
Separation
Time
Figure 6.16 One Part Detector Edge Timing