Instantel Blastmate III Operator'S Manual Download

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Chapter 3

3–8

BlastMate III Operator Manual

(5) Histogram Combo Record Mode

This mode creates a waveform during histogram recording if the signal exceeds the waveform
trigger level. The waveform event is saved as a separate file while the histogram event file
remains continuous. Up to 13 waveform events can be stored. The auxiliary trigger is disabled
during histogram combo mode.

The maximum sample rates in this mode are as follows:

4 channels or less: 2048 samples per second

more than 4 channels: 1024 samples per second

Note:

Histogram Combo record mode consumes more battery power than the Single Shot,
Continuous or Manual recording modes. We recommend connecting a monitor to the AC
adapter or an external 12 VDC power supply.

To Select a Record Mode:

Press the Record

Mode

key. The Recording Mode Window. Press the

Down Arrow

key to

scroll through the record modes. Press the

Enter

key to select a record mode when it appears on

the display.

b. Sample Rate

The BlastMate III offers three sample rates: a standard rate of 1024 samples per second, a fast rate
of 2048 samples per second, and a faster rate of 4096 samples per second (on channels 1 to 4
only). Increasing the sample rate increases the accuracy of the waveform recording. For this
reason, set the sampling rate according to the location of the standard transducer. For close–in
monitoring, set the sample rate to 4096 samples per second. For far–field monitoring, set the
sample rate to 1024 samples per second.

Aliasing occurs when a high–frequency signal appears as an erroneous low frequency because the
waveform was sampled at too low a sampling rate. An anti-aliasing filter solves this problem by
removing the high–frequencies before they can appear at lower frequencies. The BlastMate III
standard sensors have anti-alias sensors built into them to avoid this problem.

To choose a sample rate, press the Record

Mode

key. Press the

Enter

key to scroll through the

windows until the Sample Rate Window appears. Use the

Down Arrow

keys to display the

required sample rate. Press the

Enter

key to select a rate.

c. Storage Mode

The storage mode setting allows you to set the amount of data recorded with each event. In the
Store Full Waveform setting, the BlastMate III records all event data. In the Store Summary Only
mode, the BlastMate III records all event data

except

the waveforms and the Compliance Report.

WARNING:

If you choose Store Summary Only, you will not be able to re

−

create the

waveform.

To choose a Storage Mode, press the Record

Mode

key. Press the

Enter

key to scroll through the

windows until the Storage Mode Window appears. Use the

Down Arrow

keys to display

the required storage mode. Press the

Enter

key to select a mode.

d. Maximum Geo Range

(Compliance Module Only)

The Maximum Geo Range specifies the measurement limits of the standard transducer’s
geophones. Two ranges are available: Sensitive 1.25 in/s (31.7 mm/s) and Normal 10.0 in/s (254
mm/s). Choosing a maximum geophone range depends on the proximity of the transducer to the
event and the expected velocities.