17
V1.4 March 15
6.0
DATA HANDLING
The function of an instrument is to provide useful and reliable data.
Accurate recording and handling of the data is essential if it is to be
of any value.
6.1
Monitoring the NATM cell readings
Geosense
®
NPC
-
3000 NATM Cells
include both pressure and temperature sensors.
NATM cells are installed in a zone where the temperature is likely to fluctuate
significantly and therefore records of both pressure and temperature data should be
recorded. They can then be used to assess any temperature effects on the pressure
readings.
6.1.1
Portable Readouts
Geosense
®
offer a range of readout and data logging options. Specific operation
manuals are supplied with each readout device.
Below is a brief, step
-
by
-
step procedure for use with
the
RST VW2106
portable readout.
1.
Connect signal cable from the sensor to the
readout following the wiring colour code.
Conductor colours may vary depending upon
the extension cable used. Commonly these
are:
RED
=
VW +
BLACK
=
VW
-
GREEN
=
Temp
WHITE
=
Temp
2.
Switch on the unit and, where necessary, select range B
3.
The readout displays the Vibrating Wire reading ( in Hz
2
/1000
-
Linear Digits )
and a temperature reading in degrees C.
Whilst it is not critical that the polarity be observed for most Vibrating Wire
instruments, a better signal may be obtained if the correct polarity is adopted. Since
the temperature sensor is a Thermistor, its connection polarity is not important.
6.1.2
Data Loggers
A number of data loggers are available to automatically excite, interrogate and record
the reading from Vibrating Wire instruments. These include devices manufactured by
Geosense
®
/ RST in both single and multi
-
channel configurations, as well as
equipment manufactured by independent suppliers.
Geosense
®
configure and supply equipment manufactured by both Campbell
Scientific Ltd and DataTaker Ltd. These are the most commonly adopted third party
manufacturers of data loggers that can be used with Vibrating Wire Instruments.
(Continued on page 18)
