The work involved switched mode power supply design, and the development of measures for Standards compliance. Modifications to the existing design solved a problem with surge sensitivity. Australian conditions make more stringent demands than IEC Standards. The work on the new model required difficult interaction with the consumer products marketing people.

Aerosonde Pty. Ltd http://www.aerosonde.com/
Manufacturers of pilotless aircraft.
August and September 2012
(Short – term contract)

I was employed in the electronics production area. The work included electronic assembly work, testing, development of testing methods, design of test jigs. The work was only short term as it related to the completion of a particular contract.

Hydrix (http://www.hydrix.com/)
April 2010 – July 2012

Full time employment under the title “Senior Engineer”

Principal Engineer in several projects developing swimming pool chlorinators, and smaller contribution to other projects.
Detailed design of switch mode power supplies
Supervision of others (engineers, technicians, pcb layout CAD operator)
Mentorship of younger engineers
Project documentation (Requirements, Design Notes, Design Test Plan, Test Reports, manufacturing Test procedure)
Writing ISO 9001 procedures
First Aid Officer

Australian Model Engineering Magazine
2009 (continuing)

In my own column named “Sparks 'n' Arcs” I am writing a series of articles for Australian Model Engineering Magazine to explain electronics to a readership with a strong mechanical background. A sample of these are to be found at http://home.exetel.com.au/rwombat/Sparks_n_Arcs/

Omnitron Technologies http://www.omnitron.com.au/
February 2009 – November 2009
Electronic Design Engineer (contractor)

Design and development for manufacturing of a heavy current transmitter for geophysical research. I have made some advancements to the art in which very fast on and off transitions are required in current waveforms of 50 amps magnitude.
Designed the control and alarm/safety circuits.

Air-Met Scientific Pty. Ltd. http://www.airmet.com.au/
December 2004 – September 2006
(Manufacturer and import agent for toxic gas sensing instruments)

Technical Services Manager

Airmet was a small company situated in Blackburn which was a gas contaminant monitoring equipment merchant, and a developer of air contaminant monitoring equipment.

I developed an engineering documentation and release system based on html files and hyperlinks between files.
I was responsible for the mentorship and supervision of younger Engineers
I was responsible for technical and engineering support to the service team. I conducted training and acted as consultant to assist with odd-ball or particularly difficult service tasks.
I was manager of all Technical aspects (except gas chemistry matters) of the "Fixed Systems" part of the Air Met business. With this role, I designed and brought into manufacture the "Monotox 5000" toxic gas sensing instrument.

Nilsen Industrial Electronics (This company no longer exists. No web site)
Heidelberg West
(Manufactured electronic domestic kilowatt-hour meters)

1993 – 2004

When I joined Nilsen, the electronic kilowatt hour meter had been in production for some years. The new task was to develop an enhanced model. One aim was to change from Class 2 (plus or minus 2% accuracy) to Class 1 (plus or minus 1% accuracy).
This matter of product accuracy is widely misunderstood. Many component manufacturers offer components that they claim will “meet Class 1”, but on examination one finds that the component is taking up the whole of the error budget for the Class 1 product. One percent is the total error of the final product at the factory door, and includes errors due to the calibration test set, and every source of error within the product.
The new meter was designed around a Motorola 68HC11 microprocessor.
Enhancements introduced by me included:

Matching the phase response of the voltage and current inputs.
Software based phase error correction
This scheme, which was all my own work, was implemented in the meter. Some years later, salesmen from TI attempted to tell me under protection of a non-disclosure agreement about pretty much the same scheme! The idea is that if you pick two points on a sinusoidal waveform that are close together in time compared with a half period, and then do a straight line interpolation between them, then as the pair of points move along the sinusoid, the interpolation point will also be a sinusoid. As the spacing between the points is increased, the amplitude of the interpolated sinusoid will decrease. Thus the interpolation acts as a low pass filter. The use of this in the meter is that there is a standing error between the phase of the voltage path and the phase of the current path. This can be nulled if the following sequence is followed: Current measurement, fixed delay, voltage measurement, fixed delay, and then a second current measurement. Linear interpolation can then be performed on the two current measurements and by varying the weighting of each, the effective resultant phase of the composite current measurement can be varied over a small range. It is an easy matter in the test set to adjust this so that the phase of the composite current sinusoid matches that for the voltage with errors in the input circuits cancelled.

Introduction of pseudo random sequence generated dither signal
Interference cancelling and copper-drop nulled shunt circuit geometry.
Wide dynamic range optical port.

Other projects that I was responsible for included:

"Smart Probe" optical reading head with built-in protocol conversion. Hardware design (including die-cast case) and software - 6805 assembler code.
Development of a system and associated hardware called "Meternet" which allows meters to be networked for remote reading (large residential complexes) (Software by others)
Development of a provision for registering a count of pulses from sources such as water or gas meters (to incorporate "dumb" devices in remote reading systems) Utilized PIC 12CXXX processors. Used special data format (edge-time-encoded) to provide immunity to telegraph distortion and reduce cost. Software necessarily written in assembler as it manages sub-microsecond timing of the communications protocol.
Concept development for new meter model (NEC `UPD780308 based) a cost reduction exercise. (This was later in production for three years at about 40 000 units per year.)
Continuing cost reduction minor design modifications. About $10.00 per unit or $400,000 pa resulting from my innovations.

I was responsible for mentorship of younger engineers. Developed working protocols for maximum synergy for groups with diverse skills.

Variant management system

I developed the architecture and the code for a computer program which ran the process from the Sales specification to the Engineeering parts List and the pcb loading drawing for the particular build. The system was implemented and provided a huge reduction in cost in the introduction of each new variant.

Ausmode Power Systems/Exicom Australia http://www.exicom.com.au/
1988 - 1992

Ringwood Ausmode Power Systems was a small company set up to design and manufacture power equipment for the telecommunications industry.

Project Leader - Uninterruptible power supply (600 VA - for use with a pc.) True sine wave inverter and provision for synchronizing to mains on power restoration for seamless switch back.

Project Leader - Supervisory board for 50 amp rectifier. Analogue and digital controller design. Control of heavy current circuits via fibre-optic link.

Project Leader - Light-current parts of 450 amp and 1000 amp Distribution Module
Heavy Current (shunts on bus bars), and electronics design of a system that monitored energy use in the telecommunications fifty volt dc environment. The equipment had provision for monitoring various alarms and for communications for remote control/monitoring.
Managed the software development, and wrote most of the code which was in Motorola 68HC11 assembler.

Futuretech Pty. Ltd. Oakleigh
1985 - 1988

I was employed to manage the development of a frequency division multiplex equipment test system. This gave me the opportunity to delve much more deeply into the design of phase locked loops for demanding applications. This in turn led to the development of an agile multi frequency tone generator for L. M. Ericsson. For some time, I was the Project Leader for a hydrographer's telemetry system for the Dandenong Valley Authority.

Schurmann Design Pty. Ltd. , Warrandyte
1983 - 1985

This was my own company. I worked from a “home office” with one technician. Several design projects were carried out. These were the early days of applying microprocessors to small products.

I had contact with the people at the Ford Motor company warehouse, and they engaged me to take an investigatory trip to Detroit and Atlanta USA to evaluate radio link data terminal system. On my return, I installed and commissioned the system. This involved the manufacture of a special interface between the Ford Burroughs computer system and the radio terminal system.

Nielsen Development Laboratory , Fitzroy and Heidelberg
1982 - 1983

The plan was to develop a single electronic meter that would perform all of these functions. I was employed as project leader. for the development of an electronic kilowatt hour meter.

There is some controversy about who thought up what. However at the earliest part of the project, before other team members were brought in, I established some key principles. I saw the 50Hz mains waveform as a carrier. The rate at which energy is used is a varying quantity, and the waveform of this variation can be regarded as a signal that is used to amplitude modulate the 50Hz carrier. The useful bandwidth of this signal is quite a different thing from the bandwidth of the instantaneous voltage or current or power waveforms. Indeed, as the signal (rate of energy, or power) is to be integrated to get an energy, the bandwidth of the power signal can be reduced considerably without lowering the accuracy of the cumulative answer. As the cumulative answer is the result of the summation of very many samples, the samples themselves can have a much higher quantization error that is acceptable in the answer. Quite large random errors are acceptable in the samples, and these will disappear in the summation as long as they are not systematic.

Important ideas were introduced about how to demodulate the signal from the carrier, but these were not all my own.

I took this project to a stage where working prototypes had been demonstrated.

Hyteco Pty. Ltd. , Clayton
1977 - 1982

Trained in the USA on the “Pathfinder” wire guidance system for warehouse trucks that work in very narrow aisles. This system used a 6.25 kHz current in the guidewire, and sensor coils to pick up the magnetic field surrounding this. A simple analogue computer determined steering requirements (for reverse as well as forward travel) from the sensor signals. The work consisted of the development of the guidance system, (based on Pathfinder practice) a communication system to work between the master controller and the tractors and the lineside equipment (location identifiers and turnouts), and adapting all this to tractors that were designed for operation by a driver. The communications system used the guidewire as the comms channel. Traffic from the central controller was by frequency shift keying of a sub-carrier added to the guidepath current. Communications to the central controller was by phase shift keying of a carrier which was derived by multiplying the guidepath frequency by 2.5. A special receiver was immune to the guidepath frequency and its harmonics, and provided for correction of phase drifts as a tractor moved around the system.

Each tractor, and the master controller were microprocessor controlled. 6800 microprocessors were used.

I conducted training of the electric fork truck mechanics.

Prior to 1977
Various positions in which I moved through the ranks as a junior electronics engineer, and in the field of acoustics where I worked in a development laboratory and in manufacturing where I worked in production management including computer programming.

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