Microstrain

DEMOD-DVRT

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DEMOD-DVRT

Carrier Amplifier-Oscillator/Demodulator for DVRTs® Inductive, Capacitive and Resistive Bridge Circuits.

Overview

Designed for ease of use and general versatility, this printed circuit card provides complete conditioning for any of MicroStrain’s DVRT® sensors. Each card contains all the requisite components to facilitate plug-and-play use, including active, jumper selectable low pass filters, input supply line filters with reverse input protection, and output line buffers. The DEMOD-DVRT® sine wave excitation and synchronous demodulator provide excellent noise rejection and elimination of thermally induced potentials.

MicroStrain’s Motherboard products are designed to house the DEMOD-DVRT®. The Motherboards have a desktop console form factor and provide a plug-and-play chassis. The Motherboard variously provides power, grounding, multiplexing, analog-to-digital conversion, configuration, analog output, RS-232 output and LCD display. Motherboards can support 1 to 8 DEMOD-DVRT®, have a small footprint, and operate within a wide temperature range.

Operating from a DC power supply, the DEMOD-DVRT® Signal Conditioner filters incoming transients from the line voltage, and supplies a pure sine wave excitation to the transducer’s bridge. This excitation is used to measure minute impedance changes of the sensing elements. A differential amplifier raises AC input voltages in order to provide optimum demodulator performance. The output is filtered and buffered to provide clean, high level signals over coaxial cable.

The DEMOD-DVRT® is recommended for use with all standard MicroStrain DVRT® where the temperature is expected to uniformly change across the sensor itself. If the sensor is expected to be exposed to thermal gradients across its sensing coils (its body), the temperature compensated DEMOD-DVRT® -TC is recommended. Additionally, if the MicroStrain DVRT® has been customized and built with one coil, the DEMOD-DVRT® -TC is again recommended.

Typically, a DEMOD-DVRT® is ordered with a specific MicroStrain DVRT® and sold as a pair. The pair is calibrated together at the factory and delivered with a common calibration certificate. This ‘paired’ calibration insures accurate performance in the user’s hands. The certificate provides several output calculations including Linear Fit, Multi-Segment Fit and Polynomial Fit.

Designed for ease of use and general versatility, these printed circuit cards pr
Applications

Used with MicroStrain DVRT® sensors for:
• miniature control elements for automotive and robotic systems
• process control for production-line monitoring
• dimensional gauging for quality control applications
• measuring strain and deflection in materials science and civil structures
• linear/angular positioning of optical components
• miniature force, torque, acceleration sensors
• measuring strain, micromotion and deformation in bone and tissue

  • easy plug and play implementation with MicroStrain Motherboards
  • compatible with all DVRT® sensors
  • gain is factory adjustable from 10-10,000
  • short warm up time
  • demodulation is synchronous, DC output
  • operating temperature is -40°C to +85°C
  • adjustable trimmers allow user to set resolution range

Sensor types

inductive (DVRT®)

Excitation

regulated sinewave, 70 KHz typical

Demodulation

synchronous, DC output

Output

± 4.5 volts typical

Gain

factory adjustable 10-10,000

Low pass filter

2 pole, active Butterworth, 3 dB down @ 1 KHz standard; factory adjustable 10 Hz-8 Khz

Supply voltage

motherboard supplies power (typical), ± 6.5 volts min, ± 16 volts max (when used without motherboard)

Supply current

30 milliamps per rail

Warm-up time

15 minutes recommended

Operating temperature

-40 to +85˚C

PC board Size

12mm x 48mm x 20mm (thick)

Connectors

10 pin, .1" pitch header (power, ground); LEMO 4 pin receptacle (bridge points); BNC (analog output)

Trimmers

offset (std.)

 

How To Order

To discuss configuration for your specific system requirements, please contact sales at sales@microstrain.com or call  802-862-6629.

For large quantity orders or OEM discussions, please contact mirobinson@microstrain.com.

If you are outside the US, please contact one of our distributors.