MREL DATA TRAP II, Руководство по эксплуатации

Страница: 40 / 60

DataTrap II™ Operations Manual - Edition 5.4
36
5.6 DataTrap II™ Data/VOD Recorder Setup Procedure For
VOD Measurements
Once the VOD probe has been placed in the explosive and connected to the RG-58 coaxial cable running to the channel inputs
(labeled 1 2 3 4 5 6 7 8 ) on the back of the DataTrap II™ Data/VOD Recorder , the Operator can start setting the DataTrap II™ Data/
VOD Recorder to record VOD experiments. Changing the DataTrap II™ Data/VOD Recorder recording parameters, such as recording
rate, number of channels, trigger level, pre-trigger memory and allocating the DataTrap II™ Data/VOD Recorder memory to multiple tests
should all have been accomplished, if required, in the office environment through use of the DAS™ Data Acquisition Suite . Some settings
can be changed using the DataTrap II™ Data/VOD Recorder display menu.
The procedure to record a new VOD test consists of the following steps:
C A U T I O N
MREL recommends a Trigger Level of about 95% and a Pre-Trigger Time of about 25% for VOD recording of
explosives samples and explosives in blastholes.
MREL recommends setting the Number of Tests = 1 for VOD recording of blastholes using PROBECABLE . The Operator
will normally be able to download the data from the DataTrap II™ to a computer before conducting the next VOD test.
At a 10 MHz recording rate, a DataTrap II™ Data/VOD Recorder with standard memory, utilizing 1 channel per test,
will record for a total of 6.4 seconds per test if the Number of Tests = 1. This is more than sufficient recording time for
most VOD recording applications. At a 10 MHz recording rate, a DataTrap II™ Data/VOD Recorder with standard
memory, utilizing 8 channels per test, will record for a total of 800 ms per test if the Number of Tests = 1. If this is
insufficient time, then the recording rate can be reduced to increase the recording time or the Operator can double or
quadruple the Memory in the DataTrap II™ Data/VOD Recorder with the Memory Upgrade Options.
MREL recommends setting the Number of Tests = 32 for VOD recording of samples of explosives using a PROBEROD .
This reduces the quantity of data collected per test and conserves the computer’s disk space. At a 10 MHz recording
rate, a DataTrap II™ Data/VOD Recorder with standard memory, utilizing 1 channel per test, will record for a total of
approximately 200 ms per test if the Number of Tests = 32. This is more than sufficient recording time for a sample of
explosives. At a 10 MHz recording rate, a DataTrap II™ with standard memory will record for a total of 52 ms per
test if the Number of Tests = 16. This is more than sufficient recording time for a sample of explosives.
C A U T I O N
When shipped from MREL, the DataTrap II™ Data/VOD Recorders recording parameters have been pre-set to settings
appropriate for most blasthole VOD recording situations. Recording Rate = 10 MHz. Number of channels utilized
= 1. Number of tests = 1. Total Recording Time = 6.4 seconds, with standard 128 MB memory, 12.8 seconds
with optional 256 MB memory and 25.6 seconds with optional 512 MB memory. Pre-trigger Time = 25% of Total
Recording Time = 0.5 seconds. Trigger Level = 95%. These settings recommendations for VOD recording on one
channel are based on MREL’s extensive worldwide experience in VOD recording. Of course when recording multiple
channels, the recording time decreases accordingly.