VW Comm Interface Module

Communications Module with Many Faces

Three 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).

Features

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.

Cost-Effective

Low-cost wired or wireless networking

Compatible

Compatible with a wide range of sensors

Easy Configuration

Easily integrates with Campbell Scientific and Sutron MCU’s

Specifications

MiniMux Multiplexer

Channels(16) 4-channel or (32) 2-channel (switch selectable)
Control Inputs2
Control Input Range5–16V
Power10–16VDC
Power Consumption (Quiescent)<0.1µA
Power Consumption (Active)~42mA
Relay ContactsGold clad silver alloy
Contact Resistance75mΩ
Contact Isolation1500V
Coil Resistance1028Ω
Relay Operate Time~2ms
Relay Release Time~1ms
Relay Max Voltage125VAC, 110VDC
Relay Max Switching 2A
Relay Life (Minimum)108 Cycles
Transient Protection Threshold75V
Transient Current Limit1kA