Campbell CRVW3, Instruction Manual

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CRVW3 3-Channel Vibrating-Wire Datalogger
19
FIGURE 8-1. Wiring Panel of the CRVW3
Two of the sensor leads are for the main vibrating-wire measurement, and they
are wired internally to the coil-circuit of the sensor. This connection is used for
both sensor excitation (energy input) and for reading out the current
measurement (measurement output). These two leads should be connected to
the two VW terminals on the CRVW3 corresponding to the desired
measurement channel. The shield wire should be connected to the ground
associated with that channel (located in between the VW terminals and the T
terminals). If the sensor has a built-in temperature measurement device, those
two leads should be connected to the two
T
terminals.
Sensor manufacturers often color-code the leads so you can easily identify
which leads are for the coil-circuit and which are for the temperature device.
Polarity does not need to be considered when wiring the two leads for the VW
terminals and the two leads for the
T
terminals.
FIGURE 8-2. Typical Vibrating-Wire Sensor Lead Colors and
Connections
Use the provided screwdriver (pn 1113) to wire the leads securely into the
terminal blocks. Ensure a good connection between the metal lead and the
inside of the terminal.
If the built-in temperature device isn’t a thermistor, measure only
the resistance of the device in Ohms. If it is a thermistor that
follows the Steinhart-Hart conversion formula, you have the
option to convert the thermistor resistance output into Degrees
Celsius. Refer to the sensor manual to know which kind of
temperature device you have.
NOTE