LINK Systems OmniLink 5000 - Manual (Page 27)

3-6
Figure 3.9
Two Part Detector input timing
sensor used to detect the part will see only one part, causing nuisance production stops. Parts with
holes or irregular shapes can look like two parts to probes and infrared sensors, giving false signals.
When programming an input as a 2 Part Detector type, the operator must choose whether it will be
required for the second part to completely pass the detector during the timing window. If it is
desired that the second part completely pass (i.e., the detector will become inactive again before the
timing window turns off), then the input should be programmed as '2 Part Detector-Pass'. If the
second part is only required to enter the detector during the window but does not have to completely
pass through until after the window, then the input should be programmed as '2 Part Detector-Edge'.
This signifies that only the leading edge of the second part must be seen during the window. (For
information on programming the timing window, see “Programming Window Setpoints” in Section
2). Note: If the input is programmed as ‘2 Part Detector - Pass’, the sensor is not allowed to
become active outside the window or a fault will be generated. As in the case of ‘1 Part Detector
- Pass’, this provides protection against a part ‘bouncing’ on a probe-type detector and satisfying the
die protection input.
When programming an input for 2 Part type, the
operator must also program a separation time
between parts (see “Programming Separation
Time”, Section 2). The separation interval helps
in avoiding false signals. The die protection
module will delay this amount of time after
recognizing the first part before monitoring for
the second part. If the parts are irregularly shaped
or have holes that might cause a part to be
counted more than once, the forced delay will
allow the first part to get completely through the
detector without this occurring. The separation
time can be from 4 to 999 milliseconds in 1 ms
increments.
The Link 3040 Infrared Parts Detector is illustrated in Figure 3.10. Examples of other probes used