CRVW3 3-Channel Vibrating-Wire Datalogger
34
). Consider the following tasks when
installing a CRVW3 station:
•
Connecting Sensors to the CRVW3
•
Providing Power to the CRVW3
•
Monitoring and Controlling Humidity Within the CRVW3 Enclosure
•
Mounting the CRVW3 Enclosure
•
Installing the CRVW3 Antenna (for devices with a radio option)
•
Connecting the CRVW3 Electrical System to Earth Ground, Surge
Protection
•
Validating and Fine-Tuning CRVW3 Settings
•
Confirming CRVW3 Sensor Measurement Operation
•
Validating Radio communications (when applicable)
•
Sealing the CRVW3 Enclosure
Details about these tasks are provided in this section.
When installing devices with a radio option, bring a radio device into the field
that can operate as a radio base station. For the CRVW3-RF451 this is the
RF451 device configured as the master radio and
LoggerNet
software running
on a laptop computer. For the CRVW3-RF407 this is the RF407 device and
LoggerNet
software running on a laptop computer.
8.2.1 Connecting Sensors to the CRVW3
Selection of the proper vibrating-wire sensors to meet your data acquisition
needs is a process that is beyond the scope of this document. Contact an
application engineer at your local Campbell Scientific support office for
guidance regarding sensor selection and purchase. Campbell Scientific, Inc.
also provides training related to the measurement of several kinds of vibrating-
wire sensors.
The vibrating-wire sensors to be measured should be located within a
reasonable distance of the CRVW3. Install the sensors according to
manufacturer supplied instructions. A 5-wire or 3-wire cable will connect
between each sensor and the CRVW3. Longer cable distances (more than
500 m or 1500 feet) may require the use of 12 volt excitation instead of 5 volt
excitation (see Excitation Voltage in Section
(p.
). Since 12 volt excitation uses more power, consider how that excitation
level may impact your power storage. Vibrating-wire sensor connections can
provide reliable readings using cable distances up to 1500 m/5000 feet in some
circumstances. Cable distances less than 500 m/1500 ft. are recommended. Up
to three vibrating-wire sensors can be connected to each CRVW3.
Vibrating-wire sensors containing a built in thermistor will have five wire
leads. Sensors that do not contain a built-in thermistor will have three leads. A
sensor with five wire leads will have two leads for the coil circuit, two leads for
the thermistor, and a shield lead. A 3-wire sensor has two leads for the coil
circuit and a shield lead.
Color coding of wire leads for some of the more prevalent vibrating-wire
sensors is shown in FIGURE
Summary of Contents for CRVW3
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