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The procedure for connecting sensors to the MicroTrap™
VOD/Data Recorder is as follows:
1. Place the MicroTrap™ VOD/Data Recorder in a protective
shelter and/or a safe distance away from the detonation
area. This distance may be closer than what is considered
safe for the User. Once the setup is completed, the
MicroTrap™ VOD/Data Recorder does not require the
User to collect the data; it does so automatically without
assistance.
2. For each sensor you intend to use, run a length of coaxial
cable from the MicroTrap™ VOD/Data Recorder to that
sensor with enough excess length to compensate for cable shortening or cable damage from each test (if applicable). Shorter lengths
of coaxial cable may be connected together using the wire cutters and electrical tape. A male BNC connector should be attached
to the end of the coaxial cable that is to be attached to the Scope inputs (labeled 1 2 3 4) on the back of the MicroTrap™ VOD/Data
Recorder. Convenient BNC Adapters have been supplied with the MicroTrap™ VOD/Data Recorder for this purpose. The Adapters
can be connected to the coaxial cable using the wire cutters and electrical tape. The connection should be “shielding to shielding”
and “center to center” conductor. Ensure that the center conductor and the shielding do not touch each other.
3. Make note of the conversion formulas of the sensors being used. If using multiple sensors of the same type are to be used, make note
of the serial number and conversion formula of each sensor. These conversion formulas are generally used in equations that relate
voltage to engineering units. You will need to enter these conversion formulas into the DAS™ Data Acquisition Suite Software to
convert the graphs of voltage versus time, to graphs of the appropriate engineering units versus time.
4. Install your sensors in their final positions.
5. Connect the coaxial cable to your sensors using the appropriate connectors, or your wire cutters and electrical tape. Note that the
polarity of the connection is typically important to indicate positive or negative readings from the sensors. The centre conductor of
the coaxial cable is termed “active” and the shielding is “common”. Remember to connect and adjust the settings on your amplifier or
signal conditioner(s) as required.
6. Connect the coaxial cables to the Scope inputs (labeled 1 2 3 4) on the back of the MicroTrap™ VOD/Data Recorder.
7. The MicroTrap™ VOD/Data Recorder is now ready to begin the recording sequence, as detailed in Section 5.4 below.
5.3 Signal Cable Protection
It is important to protect the gauge signal cable from damage caused by personnel and machinery operating at the test area. If testing
explosives, it is also important to protect the cable from damage caused by detonation of other holes and/or surface accessories such as
detonating cord, detonating relays, and shock tube bunch blocks.
5.3.1 Detonation Cord
Experience has shown that it is best to lead the PROBECABLE and coaxial cable under the detonating cord and leave a barrier of sand or
drill cuttings between the cables and the detonating cord. A danger point is the collar area of the holes as the detonating cord or shock
tube bunch blocks that initiate the downlines may cross directly over the PROBECABLE or coaxial cable. A good procedure is to protect
the area where there is a cross over for about 1.5 m (5 ft) along the length of cable. Experience has shown that a sand or stemming
barrier thickness of 15-30 cm (0.5-1 ft) is sufficient to protect the cables.
1 2 3 4 Connectors
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