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5. Press the REMAINING TESTS button to see the number of memory slots that remain to be filled in the MicroTrap™ VOD/Data
Recorders non-volatile memory. If this number does not equal the number of TOTAL TESTS, then there are one or more tests already
stored in the MicroTrap™ VOD/Data Recorders internal memory. If the value shown on the display is 0, the memory is full and will
need to be cleared prior to conducting further tests.
6. If you intend to use the MicroTrap™ VOD/Data Recorders internal trigger, ensure the EXT/INT TRIG switch is set to the INTernal
position. The use of external EXTernal triggering is discussed in Chapter 4.8.
NOTE:
When simultaneously recording voltage and VOD data the triggering of the MicroTrap™ VOD/Data Recorder, when set on
INTernal triggering, is controlled by the VOD channel. Details on the procedure for recording VOD data are provided in the Chapter 4.
7. Look for the OUT OF RANGE warning light indicators ( and ). If there is a warning light, then the voltage being produced by one
of the sensors is out of the voltage range set by the DAS™ Data Acquisition Suite Software. If this is the case, then disconnect the
signal wires from the MicroTrap™ VOD/Data Recorder one at a time, until the warning light goes off. When the warning light goes
off, the unplugged sensor is identified as the fault. The User should test the cable connections to the sensor, as well as the power
supply and/or signal conditioner. A voltmeter should be used to verify the baseline voltage output of the sensor. If the OUT OF
RANGE lights are not illuminated the User can proceed to Step 8.
8. Press the START button. The START light will illuminate steadily. The MicroTrap™ VOD/Data Recorder then starts monitoring the blast,
waiting for the trigger signal to record the voltage data. Personnel may now vacate the MicroTrap™ VOD/Data Recorder location if
necessary.
9. When the MicroTrap™ VOD/Data Recorders internal triggering criteria is met (i.e. the voltage signal on one of the channels has
crossed the trigger level set in the DAS™ Data Acquisition Suite Software), the MicroTrap™ VOD/Data Recorder will begin recording
voltage iinformation. Note that Scope trigger is “absolute value above”. For example, if in bipolar mode and 60% trigger level is
selected with the range set to +/- 10 volts, it triggers above 6 volts or below -6 volts. Upon triggering, the TRIG’D light will illuminate
and remain on during the collection of data (this time depends on the recording rate and number of tests programmed into the
MicroTrap™ VOD/Data Recorder). During this time, both the START and STATUS lights will also be illuminated.
IMPORTANT
If the MicroTrap™ VOD/Data Recorder has triggered prematurely, or the data that you have collected is not of use to
you, then you may erase only the last test by performing the following sequence:
a. Do not turn OFF the MicroTrap™ VOD/Data Recorder after the test, the STATUS light and TRIG’D lights should
be flashing.
b. To erase the data from the last test; simultaneously press the TOTAL TESTS and REMAINING TESTS buttons
and hold them until this procedure is complete. The LED display will show ct.
c. After about 2 seconds, the ct will begin blinking. After another 2 seconds, the ct will disappear. Release the
buttons. The data from the last test has been deleted.
d. Turn OFF the MicroTrap™ VOD/Data Recorder, wait several seconds and then turn the MicroTrap™ VOD/Data
Recorder ON again. Pressing the TOTAL TESTS button and then the REMAINING TESTS button will confirm
that the remaining tests have been increased by 1 and that the last test in the MicroTrap™ VOD/Data
Recorders memory has been deleted.
NOTE: If a scope channel is in UniPolar mode, a negative voltage will cause an out-of-range error. This may be due to incorrect polarity.
Also, some sensors produce a slightly negative voltage when zero is expected, so they require a bipolar range.
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