TIIC 2016 North America: Deep Water Sensor System


University: University of Arizona
Team Members: Matthew Barragan, Alex Yudkovitz, Ausin Nawrocki, Yi Zhang, Nikitha Ramohalli 

TI Parts Used:

  • List TI parts here used in your project
  • TPS62237
  • LMP91200
  • XTR115
  • MSP430F5529
  • INA333
  • TLV314
  • SN74LV4T125
  • ADS1220

Project Description

The team was tasked with designing two PCBs that implemented a 4-20mA current loop system, with a deep water data acquisition application. The system has two parts to it, the remote station and the base station.  The remote station, which is the part which is submerged in water, has three sensors: a PH sensor, a temperature sensor and a pressure sensor. The second part is the base station which is the heart of the system; it powers the remote station through the twisted pair wire and also communicates with the remote station through the same twisted pair. Communication is done by a HART signal, the base station modulates the signal onto the power line and the remote station demodulates the signal and switches sensors based on the signal. The sensors data is sent to the base station in the form of 4-20 mA modulated signal, the base station has a current shunt to convert the current into a voltage. This voltage is sent to an Analog-to-Digital converter which sends the digital signal to the microcontroller. The microcontroller then sends the converted signal to a computer over USB, is displayed on a Labview interface on the computer The Labview program has tabs for each sensor, if you click on the sensor you want Labview sends a command over USB to the microcontroller which then sends the signal to the Hart modem to send the signal to remote station to change sensors. The HART modem on the remote station will demodulate the signal and send a command to the microcontroller. The microcontroller then sends the command to the LMP which is an Analog front end for the sensors, to change to the correct sensor. 

Features
  • 4-20mA current Loop.
  • Uses Hart to communicate over the current loop.
  • Two wire transmission
  • Has a PH sensor, Pressure Sensor and a Temperature Sensor.
  • Low Power.

Resources

Our class report will provide you with our design information such as schematics and BOMs.

User's Guide

The system uses the industry standard HART communication protocol and 4-20mA current loops to transmit analog signals and provide a power supply between remote station and base station over long distance in deep water. The remote station utilizes multiple sensor probes to collect temperature, pressure and pH pollution data, converting them to analog signals. The base station then converts analog signals to digital signals and process them by the microcontroller. As a result, the user can remotely control and monitor the environment under water. 

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