Grantronics logo Grantronics: Electronics Design Services

All facets of Industrial Electronics Design and Manufacture including:


My Background in Electronics

My interest in electronics started before leaving high school when I was introduced to the hobby of Amateur Radio. This has provided a broad foundation which has developed into a professional engineering approach to electronics design.

In 1975, I was introduced to industrial electronics as applied to variable speed motor control using phase-controlled rectifier techniques with Eddy-Current couplings and DC motors.

I completed my Electronics and Communications Certificate in 1977 specialising in the digital and communications areas.


Design Experience

In the early 1980's, products were designed using the Zilog Z80 micro-processor. These ranged from a simple sequence controller to one of the world's first all digital DC motor controllers. Single and 3-phase 240Vac and 415Vac fully regenerative models were developed. Some are still running today! A common application area was paper and film conversion machinery.


The last Z80 project was also the first to use the Intel 8031 microcontroller which is a member of the very popular 8051 family. The Z80 was connected to several 8031s via 20mA serial links to form a distributed machine control system for paper, foil and plastic film processing. The system utilised a video display and "context sensitive" illuminated keyboard. Comprehensive diagnostic and status displays were included. These systems are still in use some 10 to 15 years after they were built.


Another project used the 8031 to interface a DC servo drive positioning system for computer control via a serial port.


One of the more specialised (and fun) projects was the control system for a "bomb disposal robot" or Explosive Ordnance Disposal Vehicle to give it it's proper name. This was another multi-processor system using 8031's to control traction drives, monitor position sensors, position cameras and the robot's arm, fire weapons (some of them were really impressive) and provide status information to a remote control station.


More recent projects have been more complex and have used the higher performance 16-bit 8096 family of microcontrollers. These projects were designed with volume production in mind. For example, a very successful project required hardware and software design for a Variable Frequency Variable Voltage AC induction motor controller using the 8097 microcontroller. These controllers were so successful that they are still in production some 7 years after the initial product release. I also designed, built and programmed most of the automated test system for this family of motor controllers.


Another project included a user's control station featuring a graphic Liquid Crystal Display with a touch screen. Information was displayed in one of several user-selectable languages and included both product configuration and diagnostic facilities. This is now a major selling feature of this product.


I then provided significant hardware and software design input for a mining conveyor monitor and control system. This system included a central control panel (80C196KC) and smart input/output units using various members of the PIC family (16C84 and similar). The I/O units monitored various safety trip wires and the operation of other conveyors and were located up to 1000m from the central controller. Being designed to operate in underground coal mines, the system included an Intrinsically Safe power supply and data interface. A voice enunciator (another 80C196KC) was added to provide spoken messages when fault conditions occurred.


Mid 1997 saw us doing a production run of an RS-232 Switch for a Point-Of-Sale system. The application required one more serial port than was available and the switching had to be done under software control. The switch runs at 9600bps and has various power supply options including 3V to 12V from the Cash Register or 9V from a PlugPak. We used the very capable Atmel AT89C2051 microcontroller (an 8031 in a 20-pin package).


In early 1998, we were approached by the local railways authority to solve an audio problem. The existing system included extended volume control wiring which was picking up interference from switching relays. We designed and supplied a PCB which used the existing volume control potentiometers to control Voltage Controlled Amplifiers so the sensitive low-level audio signals were not exposed to the interference. (no microcontroller in this project!)


Another job for the railways was a controller to decode DTMF tones and monitor audio from the control radio to control a CD player. These are mounted in heavy locomotives with lots of vibration and temperature variations. No failures to date.


A company had a very sophisticated gate access controller that used finger-print recognition. To gain access to the keypad, the user's hand was detected by Infra-Red optics and a small DC motor was used to open an access cover. The electronics controlling the DC motor and IR optics was unreliable - the existing micro appeared to crash with undervoltage conditions. We designed a replacement controller which has not had a single failure to date.


We designed and manufactured a control system for a gaming table. There is a central control board that controls 2 or 4 banks of 32 triacs (lots of flashing lights!) and a control console with 2x16 LCD for the table operator all linked together using RS-485.


We have designed several variants of a system to interface security system control panels to the GSM cellular phone network.


We developed a low-cost high-performance controller for an automatic test machine. The controller measured air pressure, had 12 lines of 24V digital I/O, 3 serial ports (1 x RS232, 2 x RS485) and a remote console. We used the Atmel ATMega103.


We have designed and built a special data switch for use with a Point Of Sale terminal. One RS232 port could be switched to either RS232 or RS485.


October 2000: We are developing a controller to monitor charging current and voltage for a manufacturer of large lead-acid traction batteries. The controller will include a menu to allow the operators to select battery type. A central PC will collect real-time data over an RS-485 network using the Modbus protocol.


For all of these projects (and others), my principal duties were the digital and analogue hardware design and the software design and implementation. Other responsibilities included developing and maintaining automated production testing facilities which I integrated into the production control system.

In industry, systems using microcontrollers are more flexible, more reliable and easier to use than systems using older techniques. Often, features may be changed by software changes only thus avoiding expensive tooling changes.

Common features of all my past projects using microcontrollers are that available resources are always limited (therefore, cost effective) and that the project has to operate in real-time using interrupts to provide acceptable response and performance. Also, these projects had to perform reliably in environments with high levels of electrical noise.


Corporate Aims


Resources

Grantronics is part of a network of engineering professionals with extensive experience in Industrial Electronics design and manufacture. We can draw on the experiences of our collegues to provide a professionally engineered solution.


A Grantronics design works.


Home

Grantronics Home Page


Last updated: 13 October 2000

Copyright 2000, Grantronics Pty Ltd