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For example, at a 95.3% Trigger Level and with 250 metres of PROBECABLE loaded into blastholes, then 28 metres of PROBECABLE must
be consumed to trigger the MicroTrap™ VOD/Data Recorder. If the first hole does not consume a sufficient length of PROBECABLE to
trigger the MicroTrap™ VOD/Data Recorder, then all of the VOD data for the first hole will be before time = 0.
The Operator should ensure that there is sufficient Pre-Trigger time to record the time it takes for the trigger length of PROBECABLE to be
consumed in the blast. This is particularly important if several delayed holes must be detonated in order for sufficient PROBECABLE to
be consumed. The MicroTrap™ VOD/Data Recorder has a very large memory and a very long Total Recording Time. At a Pre-Trigger %
setting of 25%, the MicroTrap™ VOD/Data Recorder has a long Pre-Trigger Time. It is likely that there will always be sufficient Pre-Trigger
Time to record the time it takes for the trigger length of PROBECABLE to be consumed in the blast.
If there is insufficient Pre-Trigger time, the best procedure is for the Operator to re-program the MicroTrap™ VOD/Data Recorder using
the DAS™ Data Acquisition Suite Software and increase the Pre-Trigger % to increase the amount of Pre-Trigger Time to suit the test.
Alternatively, the Operator can reduce the Recording Rate to increase the amount of both Pre and Post-Trigger Time. It should be noted
that the minimum sample rate recommended for VOD measurements is 1 MHz.
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