ARC Simulator

Student Technician II, Automation Laboratory
Software development of an electrical arc simulator.
Spring 2001
References: Dr. Behbood Zoghi, Tim Ash (AEI)

This project, sponsored by Advanced Energy Industries, was to
create a system that can emulate an electrical arc. This system will be used in
the testing and development of intelligent power supplies, primarily used in the
semiconductor manufacturing industry to automatically compensate for destructive
arcs that occur in plasma chambers. By detecting these arcs, the power supply
can reduce output power until the arc disipates and then resume normal output
power, thereby minimizing the damage caused by the electrical arc. The emulator
consists of three major parts: windows software to allow the user to program the
desired arc pattern, a General Purpose Interface Bus (GPIB) card to program a
function generator, and a coupling circuit to bridge the output of the function
generator to the feedback line of the intelligent power supply. For testing
purposes, an arc can be simulated by the function generator by dropping the
voltage from 10Vdc to some lesser amplitude (usually 0V), and back to 10V. This
will simulate a short circuit seen when an arc takes place. The Arc Simulator is
capable of generating any combination of arcs ranging from 1us to 10,000
seconds, specifying the arc amplitude setpoint and arc voltage for each arc. The
windows application was developed in Borland C++ Builder 5.0. This project gave
me an excellent opportunity to develop skills in visual programming, and gain
experience using GPIB.

Pressure Transducer

Student Technician, Automation Laboratory
Firmware development of a pressure transducer.
Fall 2000
Reference: Dr. Behbood Zoghi

For this project, I was to write the firmware for a
microcontroller based Pressure Transducer
for Control Systems
International. Specifically, I wrote assembly language for the MC68HC705J1A microcontroller to control and monitor pressure
in a chamber through a valve. This involves many techniques and skills such as a
closed loop control algorithms, reading and generating pulse width modulation,
communicating between devices both on the PCB board and off of the PCB board,
utilizing hardware and timer interrupts to their full extent, and
creating/maintaining a complex button and decimal LED driven user interface.
This has been a huge learning experience for me. In higher level
microcontrollers and programming languages, much of this is taken care of for
you. The microcontroller might already be capable of doing complex math, reading
PWM, performing A/D operations, etc… But in the case of the 68HC05, your world
becomes much
smaller.

This is an 8 bit microcontroller with a few hardware interrupts,
a couple of timer interrupts, and that’s about it. A big problem during this
project was constantly running out of EPROM space. The 68HC705J1A only contains
1231 bytes of usable EPROM. Considering the complexity of the pressure
transducer and the many modes of operation and control it was capable of, I had
to become very creative and efficient to write the smallest code possible. To
add to this problem, because it is only an 8 bit microcontroller, it was
necessary to constantly check for overflow during math operations.

To avoid this, many calculations were broken into an upper and
lower nibbles so they could be operated on separately. This meant that simple
math could take paragraphs of code. Complex math, such as divide, simply did not
exist as an op code. Using the available multiply function, I had to create my
own divide function, of course with integer resolution, no floating point
calculations allowed. The point is, all of these obstacles, despite the
headaches, made for a very educational experience, problems faced in the real
world you might say. This also made the project fun. A problem arose, I worked
on that problem till it was solved, and then continued working till a new
problem arose. And usually the kind of problems experienced were things that I
never could have anticipated at the beginning of the project. This extended the
project timeline farther than I had anticipated, but made for an interesting and
beneficial project.

Supply Chain Management Compiled HTML Help File – Automation Lab

Student Technician, Automation Laboratory
Created a help file for a business application that was being developed by the Automation Lab.
Spring 1999
Reference: Dr. Behbood Zoghi

I am a student technician in the Automation Laboratory. My
job was to write an HTML Compiled Help file for a Supply Chain Management
business application being created by Underhill & Associates. Basically I wrote help
documentation for a software package that was being created. Admittedly, this
was not the most exciting experience, but it was a very valuable experience
relating technical skills to real world applications, and it is exciting to
think that the work I did will hopefully be put to use by major corporations
sometime in the future. Plus, this job was my foot in the door to a great lab and employer where I eventually got to work very cool projects. I learned a lot while working the Automation Laboratory.