Sensor SMT-200 Operation And Technical Manual page 71

SENSOR
Io
5.1 Preparing the SMT-200 for use
Before configuring the SMT-200 to test a new type of string ensure the full details of the string are
known, including:
• geophone type (specification).
• damping resistor value (if installed).
• number of elements in series connection.
• number of elements in parallel connection.
• case interval.
• lead-in.
• connector polarity.
If there is a large temperature
differential between these points
the temperature sensor may have
to be moved. See Appendix A
(Section A.6) for more details.
First thing to do is check that the geophone type is in the SMT-200 library. If the geophone type is not
listed in the SMT-200 library copy it from another geophone description and edit the required
parameters accordingly.
1. Switch on.
2. Select Setup menu 2.
3. Select Geophone menu 2.
4. Go to Select menu 1.
5. Place the cursor alongside the geophone specification for the elements in your string.
6. Hit
ENTER/START
7. Type 0 to return to the Setup menu.
8. Select String menu 1 to set your string characteristics.
String menu
----------------
1>No. 26
2 Series 12
3 Parallel 1
4 Rcab 126 Ω/km
5 Interval 5.0 m
6 Lead-in 10.0 m
7 Use Shunt? no
8 Shunt 1000 ohm
0 Back to Setup
+ Imp/Met-------
Enter next test
or string number
SMT-200 Operations and Technical Manual 2.00/R1
to select the required element.
For a 6 x 2 series parallel string with 1000 Ω damping resistor, 5m geophone
interval and a 2.5 m lead in, the SMT-200 would be setup as shown.
The Interval, Lead-in and Rcab must be specified. The geophone resistance
test compensates for the additional resistance of the cable. If these three
entries are incorrect the resistance test could fail as the SMT-200 will
assume the extra resistance to be due to an abnormal coil or resistor.
NOTE: It is also convenient to load the new geophone specification from the
PC Docking Station software. Please see section 3.
Section 5 Geophone Testing
Terminate the geophone
lead with a suitable
connector.
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