Team:• Ryan Williams (EE)• Jonathan Wolff (EE)• Damon Soto (EE)• Jason Meyer (EE)
Advisor: Helena Silva (ECE)
Trans-Tek Contacts:• Mark Bennett• Jeffrey Gladu
Introduction
• Trans-Tek Background• Linear Variable Differential Transformers (LVDTs)• Current Oscillator/Demodulator Models• Goals• Oscillator• Demodulator• Timeline• Budget
Outline
• Founded in 1967• Located in Ellington, CT• Leading manufacturer of Linear and
Angular Displacement, and Linear Velocity Transducers
• Use Linear Variable Differential Transformers (LVDTs)
• Applications in position and velocity sensing
Trans-Tek
• Consists of a 3-part transformer
• Secondary coils wired in subtractive configuration
• Position of core determines output voltage
• Linear relationship between core position and output voltage http://upload.wikimedia.org/wikipedia/commons/0/07/
Lvdt_how.gif
LVDTs
Oscillator/Demodulator Models
• Model of Focus: • Series 1000
Oscillator/Demodulator
• Issues:• Size• Digital Signal Processing (not
used currently)
• Re-Engineer• Using specifications provided
to us by Trans-Tek• Size constraints, input/output
and component hardware
www.transtekinc.com
Goals• Use Digital Signal Processing (DSP) preferred over
hardware method.• Size Restraint: 0.700” DIAMETER TUBING, LENGTH T.B.D.• Series 1000 Oscillator Demodulator
• Maintain accuracy and reliability• manipulate product dimensions
• Oscillator:• maintain sinusoidal output, <1% harmonic distortion
• Demodulator:• Maintain non-linearity <.03%
Oscillator
• Hardware circuit that converts a DC signal to an AC signal.
• Frequency of the oscillator is determined by a RC combination, looking for a range of 1.5 to 12.5 kHz.
• Output voltage determined by a resistor, looking for 1 to 6 VRMS.
• Need to make an oscillator with almost no harmonic distortion.
http://www.electronics-tutorials.ws/oscillator/osc22.gif
• Can be performed using a hardware circuit or DSP• Hardware Circuit• No coding required• Same process used in
current models• DSP• Easier to modify and tune• More accurate• No circuit components
needed
http://www.singer-instruments.com/sites/default/files/images/tutorials/how_lvdt_works_fig3.gif
Demodulator
• Input impedance of 1MΩ or higher• 4 separate selectable output
ranges• Ripple voltage less than 0.2%• Non-linearity less than 0.03%• Temperature coefficient best effort
(± 1%)
Demodulator Specifications
Timeline
September October November December January February March April MayMeet with Sponsor Project Statement Project Specs Proposal Presentations Research Parts Written Proposal Schematic Order Parts Protoboard Build Final Presentation Final Report Debug PCB Build
Inventory•Flexible PCB •Microcontroller •LVDTs •Proto Board for experiments • 0.7 inch tubing•Component parts for the Ocillator/Demodulator •Other Parts TBD
Budget• All required materials supplied by Trans-Tek• Need to buy:• Flexible PCB• Microcontroller/DSP• Component parts for proto-board and PCB
• Total will amount to < $1000