The CDM-VW305 is an 8-channel interface between sensors and dataloggers that allows shorter intervals between measurements. This interface uses an excitation mechanism that maintains the vibrating-wire sensor in a continuously vibrating state. The interface measures the resonant frequency of the wire between excitations using the patented vibrating-wire spectral-analysis technolgy (VSPECT™). VSPECT provides very fine measurement resolution and also limits the influence of external noise by discriminating between signal and noise based on frequency content. Because of this technology, the signal can be carried through longer cables, giving flexibility in sensor and datalogger siting.
The CDM-VW305 interfaces with standard vibrating-wire sensors, giving much faster and better measurements without having to purchase new sensors. The analyzer allows high data rates, and multiple CDM-VW305 modules can be connected to one datalogger. The CDM-VW300 is similar to this item, but has 2 channels. U.S. Patent No. 8,671,758.Read More
In addition to the dynamic vibrating-wire measurement, the CDM-VW305 makes several auxiliary measurements. A static vibrating-wire measurement is made once each second, along with the dynamic measurements, which provides finer measurement resolution and greater immunity to external noise sources. The CDM-VW305 includes a thermistor input channel paired with each vibrating-wire channel, featuring high-precision 24 bit measurements at a 1 Hz rate. Lastly, a rich set of diagnostic parameters is provided with the vibrating-wire data.
The CDM-VW305 has the capability to simplify post-processing of data by computing common values internally. Vibrating-wire data can be reported as measured frequency or as the frequency squared with a multiplier and offset applied. The thermistor data is reported as resistance or is converted to degrees Celsius using the thermistor’s Steinhart-Hart coefficients. The CDM-VW305 also can internally compile rainflow histograms from the final data and report the values at user-specified intervals.
|-NOTE-||Electrical specifications are valid over a -25° to +50°C range unless otherwise specified. Non-condensing environment required.|
|Scan Rates||20, 50, 100 Hz|
|CPI Baud Rate||Selectable from 25 kbps to 1 Mbps|
|Input Resistance||5 kΩ|
|Excitation Voltage Range||0 to ±3 V (6 V peak-to-peak)|
|Excitation Voltage Resolution||26 mV|
|Operating Temperature Range||
|Measurement Frequency Accuracy||±(0.005% of reading + Resolution)|
|Sustained Input Voltage without Damage||-0.5 to +7.1 V|
|Dimensions||20.3 x 12.7 x 5.1 cm (8 x 5 x 2 in.)|
Measurement Resolution at Sample Rates
|-NOTE-||Typical values for a 2.5 kHz resonant sensor|
|1 Hz Sample Rate||0.005 Hz RMS (noise level)|
|20 Hz Sample Rate||0.008 Hz RMS (noise level)|
|50 Hz Sample Rate||0.015 Hz RMS (noise level)|
|100 Hz Sample Rate||0.035 Hz RMS (noise level)|
Sensor Resonant Frequency Range
|20 Hz Sample Rate||
|50 Hz Sample Rate||
|100 Hz Sample Rate||
|Completion Resistor||4.99 kΩ 0.1%|
|Excitation Voltage||1.5 V|
|Resolution||0.002 Ω RMS (@ 5 kΩ thermistor resistance)|
|Accuracy||0.15% of reading (Thermistor accuracy and resistance of the wire should be considered as additional errors.)|
|Measurement Rate||1 Hz|
|Voltage||9.6 to 32 Vdc|
|Typical Current Drain||190 mA (@ 12 Vdc)|
The SC-CPI Datalogger Serial-to-CPI Interface is required to connect the CDM-VW305 to compatible datalogger (except the CR6). A 5-conductor cable connects the datalogger to the SC-CPI, and an Ethernet cable connects the SC-CPI to the CDM-VW305.
The datalogger operating system must be version OS 26 or newer.
None of our retired dataloggers are compatible.
The CDM-VW305 is not designed to work with multiplexers.
DVW Tool Box is an application-specific software tool for demonstration and evaluation of the CDM-VW300 and CDM-VW305 dynamic vibrating-wire interfaces.
Execution of this download installs the CDM-VW300/305 Operating System on your computer for upload to the CDM-VW300/305 device with Device Configuration Utility.
Note: The CDM-VW300/305 OS V.02 or greater is required to use the CDM-VW300/305 with the CR6 datalogger or with a CR3000/1000/800 datalogger that is using OS 28 or higher. The SC-CPI Operating System will also need to be upgraded to SC-CPI OS V.02. If using a CR3000/1000/800 datalogger with an older OS, an operating system upgrade to the datalogger will be required.View Update History
CRBasic program examples for use with the CDM-VW300 and CDM-VW305.
A software utility used to download operating systems and set up Campbell Scientific hardware. Also will update PakBus Graph and the Network Planner if they have been installed previously by another Campbell Scientific software package.
Supported Operating Systems:
Windows 10, 8.1, 8, and 7 (Both 32 and 64 bit)
The CPI Calculator is a downloadable Microsoft Excel spreadsheet used to estimate the usage and capacity of a CPI network. The calculator provides an overview on CPI devices including the CDM-A108, CDM-A116, CDM-VW300, CDM-VW305, and the CSAT3B. The calculator can also estimate the measurement speed of the CDM-A108 and CDM-A116 based on the number of channels and measurement parameters.
The CPI Calculator is an estimation tool and will help you better understand and design CPI networks by considering the following:
Number of FAQs related to CDM-VW305: 8
Expand AllCollapse All
These devices work with vibrating-wire strain gages, load cells, pressure transducers, crackmeters, and tiltmeters. Any standard, single-coil circuit vibrating-wire sensor should work with these devices.
The frequency outputs generated by the CDM-VW300 or CDM-VW305 can be scaled with known sensor response functions, which are provided by the manufacturer of the sensor. These frequency conversions are used to obtain measurement outputs expressed in the desired engineering units.
Yes. When more than eight channels are needed in a system, multiple CDM-VW300-series devices can be connected to the same datalogger.
Any combination of CDM-VW300 and CDM-VW305 devices can be used to achieve the desired number of total terminals.
The list below, ordered by datalogger and measurement rate, indicates the maximum number of supported terminals:
To communicate with CDM devices using the CPI protocol, the CR3000, CR1000, CR850, and CR800 dataloggers require an SC-CPI device. Only one SC-CPI device per datalogger is required. It is expected that the design of future Campbell Scientific datalogger products will work with CPI-based modules directly.
CDM-VW300-series devices can measure vibrating-wire sensors at the following rates: 1 Hz, 20Hz, 50Hz, 100Hz, 200Hz, and 333.3 Hz. CDM-VW300-series devices are designed for measurement periods of 1 s or less.