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TEST CYCLE DETAIL
The inspection cycle comprises the following steps:
1. The LH200 begins the test cycle by awaiting the assertion of the ENABLE signal from the PLC or the
SQ100 (high on gray wire, connector pin 5).
2. Prior to assertion of the ENABLE signal, the test sample is indexed into position between the sensing
face of the LH200 and the illumination device..
3. The PLC then sends the ENABLE signal to the LH200 or SQ100 sequencer. The sequencer generates
individual ENABLE signals for the LH200 units on each lane of the tester or press. The ENABLE signals
are generated 1 millisecond apart to insure that no two lanes flash at the same time.
4. The ENABLE signal passes from the PLC or SQ100 to the LH200 (high on gray wire, connector pin 5)
indicating the end is in position for inspection.
5. The LH200 responds immediately to the ENABLE signal by turning the report LED off then takes 128
consecutive light readings and averages them as a dark reference. The dark reading interval plus delay
lasts 5.25 milliseconds.
6. After the dark readings are taken, the dark level average is tested against the dark limit and the dark
spread is tested against the spread limit. If either limit is exceeded, the amber LED is turned on.
7. The LH200 awaits the end of the 5.25 mS interval then asserts the STROBE signal, activating the flash
(yellow wire, connector pin 4 set high) and captures the peak light resulting from the flash.
8. When the 1 millisecond peak capture interval has expired, the captured peak value is compared to the
leak limit. If the peak value exceeds the limit but the dark average and dark spread are within limits, the
result LED is set to red. If dark average, dark spread and peak are all within limits, the report LED is set
to green. If either the dark level or the spread of the dark level readings exceeds limits, the report LED
remains amber even if the peak value exceeds its limit.
9. The LH200 delays another 3.5 milliseconds then releases the STROBE signal (yellow wire, connector
pin 4 set low) and, if no leak, sets the RESULT output high (white wire, connector pin 1). The delay
insures a quiet power supply in the flash unit until all later lane inspections have been completed.
10. The LH200 controller then sends the results of the inspection to the serial output (pink wire, connector
pin 6, 38400 baud). This is an RS-232 signal that may be connected to the serial port of a terminal or
computer.
11. The LH200 then awaits the release of the ENABLE signal (low on gray wire, connector pin 5). When
released, the RESULT output is set low (white wire, connector pin 1) and the cycle begins again at step
1 above.
See Timing Diagram below.
6
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