[Executive Summary] [Problem Statement] [Solution] [Team]
BAE Systems is a designer of aircraft controls. Their controls have a long track record of being of the highest quality to ensure their products keep the aerospace industry safe. To do this, they perform testing both before installation and also after their equipment is installed in the aircraft. Two things that they are able to test for are a shorted-out resistor or a failed switch contact by monitoring current and voltages. Our senior project group was given the task of creating a system to help identify problems such as the shorted-out resistor and failed switch and to warn the user when a problem is detected.
1. Design a voltage sensor interface that measures a DC voltage between -50 and +50 volts, or an AC voltage with a peak to peak value of 100V. This sensor can only have a 1% tolerance error.
2. Design a current sensor interface that measures a DC current between -1 and 1 Amp, or an AC current with a peak to peak value of 2 Amps. This sensor can only have a 0.75% tolerance error.
3. Condition the current and voltage inputs to go through an analog-digital converter.
4. Design an FPGA to monitor the voltage and current values from the analog-digital converters of both the voltage and current sensors. Then compare these voltage and current inputs to some user-defined threshold values. These values will then need to be able to be read and written to from a PC via a RS-232 connection.
The following is the block diagram that we used to build our project. It was given to us by our sponsors.
James Dougherty and Andy Blessing designed the circuitry for the current and voltage monitors. The voltage monitor was a simple voltage divider circuit. Instead of building a current monitor, they purchased one from an outside vendor. This cut down on the complexity of the circuit and saved time. These circuits were then put into an op-amp to condition the signals for the analog-digital converter.
Paul Bard and William Evans were in charge of the FPGA. The Spartan 3e starter board was used. The board contained an analog-digital converter, the Spartan 3e FPGA, LEDs, and a RS232 connection. Having all this onboard allowed us to concentrate more on the VHDL code. William handled the analog-digital converter code and Paul designed the code that communicated with the RS232 connection.
Students
Paul Bard
William Evans
James Dougherty
Andy Blessing
Sponsors
Bryan Berical
Joseph Fledderman