• Includes RS-232 / RS-485 / SDI-12 interfaces
  • Low-cost wired or wireless networking
  • Compatible with a wide range of sensors
  • Reliable vibrating wire measurements
  • Internal battery and temperature measurements
  • Voltage input with 4-20 mA optimization
  • Very low quiescent power consumption
  • Digital outputs for control applications
  • Switched 12 VDC connection for device control
  • Easily integrates with Campbell Scientific and Sutron MCU’s


  • Controller | Microchip PIC18F4580
  • Program Memory | 32 K Flash
  • Interface | RS-232 / RS-485 / SDI-12
  • Communications Speed | 1200-115 K bps
  • VW Measurement Range | 100-6000 Hz
  • VW Sweep Range | 100-6000 Hz
  • VW Resolution | 0.1 µs/cycles
  • Temperature Input | YSI44005
  • Temperature Input Range | –40 to +100° C
  • Temperature Accuracy | ±0.5° C
  • Voltage Input Ranges | 0-2.5, 0.5-2.5 VDC
  • Voltage Input Resolution | 10 bit (1 part in 1024)
  • Operating Power | 6-16 VDC, max 50 mA
  • Operating Temperature | –40 to +65° C
  • Quiescent Power | < 500 µA
  • Dimensions (L×W×H) | 140×75×25 mm
  • Mounting Dimensions | 127×51 mm

vwcommmodule_product_picThree industry standard communication interfaces are included: RS-232, RS-485 and SDI-12. The RS-232 interface provides compatibility with a wide range of standard wireless adaptors and modems including those from Digi International and Freewave, facilitating the deployment of cost-effective networks of wireless sensors.

The RS-485 interface allows an inexpensive, reliable wired network to be built using simple twisted pair cabling. Up to 61 nodes are supported in a wired network, with up to 1200m (4000’) of cabling. The network can be easily extended with RS-485 repeaters.

The vibrating wire interface consists of a precision differential amplifier with band-pass filtering, which improves noise rejection and measurement reliability. The excitation and measurement parameters are programmable to support all commonly used vibrating wire instruments. Reading output can be programmed for digits (Hz^2×10–³), frequency (Hz) or period (μS).

The VW Comm Module also includes support for reading YSI44005 type thermistors to provide sensor temperature measurements. Other thermistors or temperature devices are supported as well.

In addition to the vibrating wire and thermistor input capability, a single-ended voltage up to 2.5 VDC can be measured. A high accuracy 2.5 VDC reference is also provided for powering other sensors such as RTD’s and linear potentiometers. 10-bit measurement resolution can be improved with configurable averaging. The voltage input range can be offset from 0.5 to 2.5 VDC to optimize the resolution for 4-20 mA sensors. The VW Comm can also read the power supply voltage and internal temperature.

The complete list of features and specifications are detailed on the VW Comm Module Data Sheet