The AVW200 is a vibrating-wire analyzer module that allows our dataloggers to measure vibrating-wire strain gages, pressure transducers, piezometers, tiltmeters, crackmeters, and load cells. These sensors are used in a wide variety of structural, hydrological, and geotechnical applications because of their stability, accuracy, and durability.
The AVW200 uses vibrating-wire spectral-analysis technology (VSPECT™). VSPECT observes the incoming sensor signal, performs a Fourier transform and a spectral analysis (transforming the time series into indivdual sinusoidal components in the frequency spectrum), and determines the sensor frequency by identifying the largest signal in the acceptable range and disregarding noise.Read More
The AVW200 uses an innovative spectral-interpolation method for measuring the sensor’s resonant frequency. With the spectral interpolation method, the analyzer module excites the vibrating-wire sensor, measures the response, performs a Fourier transform on the response, and returns the result with a resolution better than 0.001 Hz—all within two seconds. Because spectral analysis can distinguish signal from noise on the basis of frequency content, this method offers improved immunity to competing noise.
The AVW200 analyzer module also provides many self-checking diagnostics such as vibrating-element signal strength, signal-to-noise ratio, vibrating-element signal decay ratio, and incorrect signal response. These diagnostics can be running in the background to give continual feedback of the condition for each sensor.
|-NOTE-||Electrical specifications are valid over a -25° to +50°C range unless otherwise specified. Non-condensing environment required.|
|Number of Vibrating-Wire Sensors Measured||Up to 2 vibrating-wire sensors can be connected to the analyzer module. Additional sensors can be measured by using an AM16/32-series multiplexer.|
|Power Requirements||9.6 to 16 Vdc|
|Analog Input/Outputs||2 differential (DF) vibrating-wire measurements (V+ and V-) and 2 single-ended (SE) ratiometric resistive half-bridge measurements (T+ and T-) for vibrating-wire sensor's onboard temperature sensor.|
|Digital Control Ports||
3 digital control ports (C1 – C3)
|RS-232 Port||1 9-pin RS-232 port (for connecting to a data logger COM port)|
|Measurement Resolution||0.001 Hz RMS (±250 mV differential input range; -55° to +85°C)|
|Measurement Accuracy||±0.013% of reading (±250 mV differential input range; -55° to +85°C)|
|Input Voltage Range||±250 mV (differential) for vibrating-wire inputs|
|Common Mode Range||±25 V|
|Baud Rates||Selectable from 1200 to 38.4 kbps. (ASCII protocol is one start bit, one stop bit, eight data bits, and no parity.)|
|CE Compliance Standards to which Conformity Is Declared||IEC61326:2002|
|Dimensions||21.6 x 11.18 x 3.18 cm (8.5 x 4.4 x 1.25 in.)|
|Weight||0.43 kg (0.95 lb)|
Typical Current Drain @ 12 Vdc
|Quiescent, Radio Off||~0.3 mA|
|Radio Duty Cycling 1 s||~3 mA (includes quiescent current)|
|Radio Always On||~26 mA (radio transmit current 100 mA)|
|Active RS-232 Communication||~6 mA (3 s after communication stops, the current will drop to the quiescent current.)|
|Measurement||~25 mA (averaged over the 2 s)|
Please note: The following shows notable compatibility information. It is not a comprehensive list of all compatible products.
|CR5000 (retired)||The CR5000 supports the SDI-12 mode only.|
|ENC10/12||If using the RS-232 port, the AVW200 must be mounted flat to fit in an ENC10/12.|
|ENC12/14||If using the RS-232 port, the AVW200 must be mounted flat to fit in an ENC12/14.|
The AVW200 Vibrating-Wire Spectrum Analyzer Module allows our data loggers to measure vibrating-wire strain gauges, pressure transducers, piezometers, tiltmeters, crackmeters, and load cells.
When using SDI-12, a three-conductor cable is required; Campbell Scientific recommends the CABLE3CBL-L cable. When using RS-232, the module attaches to the data logger’s RS-232 port via the 18663 null modem cable, or attaches to control ports on a CR800, CR850, CR1000, or CR3000 datalogger via the 17855 data cable.
The AVW200 requires a desiccated, non-condensing environment. A Campbell Scientific enclosure is recommended when the analyzer module is in the field. The AVW200 has built-in keyhole flanges for mounting to an enclosure backplate.
The AVW200 is typically powered by the data logger's power supply.
Number of FAQs related to AVW200: 9
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The AVW200-series modules are not required, but they do reduce the chance of erroneous readings by filtering electrical noise that is sometimes present.
Two probable causes are the following:
The AVW200 must be wired directly to the data logger via a cable.
The AVW206, AVW2011, and AVW216 have built-in spread-spectrum radios tuned to different frequencies that allow the data logger to communicate with a remote AVW device through an appropriate radio link.
Yes, using a null modem cable.
It takes 2 s for the AVW200-series modules to acquire a measurement from each sensor. An AVW200-series module servicing two AM16/32B multiplexers, each with 16 vibrating-wire sensors, requires approximately 64 s to acquire data.
Use pn 17855, Data Cable, RS-232 Male to Pigtail.
Dozens of AVW200-series modules can be accessed through one CR1000. The limiting factor is the frequency at which the CR1000 is set to retrieve data from each module. If the CR1000 needs to collect data very frequently from the modules, fewer AVW200-series modules can be accommodated in the time between data collection events.
Two multiplexers, each with a maximum of 16 or 32 sensors per multiplexer, can be attached. If temperature measurements are excluded from each sensor, 32 sensors are possible.