Wireless RTD Transmission

1. Joel Burke Ben Miller Noah Myers • Wireless Transmitter/Receiver • Loop powered transmitter (4-20 mA) • Transmission intervals based on current in 4-20 mA loop • Wireless output (Bandwidth 902-928 MHz) rated to 1000 feet • Receiver outputs current • RTD • Resistive Thermal Device • Change in temperature causes change in output resistance (three wire) • Inserted into pipe to read asphalt temperature • Currently in place in existing facilities • Problem Statement • Determine feasibility of transmitting resistance values wirelessly from an RTD • Build a prototype to test functionality • Determine parts and processes for full scale implementation • Constraints • Wireless transmission up to 1000 feet • Operate in temperature range of 250-400 ºF • Be as accurate as wired system +/- 5º • Sample at frequency of 1 sample/min • Mimic existing wired system in functionality • Future Additions • Implement microprocessor for error checking • Design large scale system for 200 components 4-20 mA Loop Power Supply Wireless Transmitter RTD 4-20 mA RTD Transmitter Wireless RTD Transmission Radio Connection System we designed • 4-20 mA Transmitter • Receives three wire RTD input • Regulates current in the 4-20 mA loop proportional to RTD resistance • Connects in series with wireless transmitter • UIRO • Universal Input Resistance Output • Receives current from transmitter - outputs three wire resistance • 256 discrete intervals of 0.4 Ω • Useful in range of 0-400 ºF (93 - 200 Ω) Wireless Receiver UIRO Controller 15 V DC Power Supply 24 V DC Power Supply Test Results Receiver and Output Wiring Diagram Transmitter Wiring Diagram