Microprocessor Control Systems 

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I shifted my career from the university environment back into industry. I was able to move into development of microprocessor control systems because of my experience gained working at the university, specifically: "interface electronics", programming microprocessor systems and interfacing microcomputers to "control and monitoring electronics". 

I started work at a small consulting company that had won a large contract from a mining supply company to design a networked outstation to meet the British Coal specification for controlling underground mining equipment via the MIDAS System.

My part was to develop, the "head-end and outstation modem cards", "outstation network protocol card" and "integration into the new outstation" that was being designed by the consulting group. 

UK HSE was very strict with regard to the technology and "energy" they would allow into underground an "Intrinsically Safe" environment. As a consequence, the choice of processor for the network protocol card was limited to a low power Intel 8085. The network protocol was a master/slave SDLC like protocol with "fail safe timers" added for network and equipment failures. The physical modulation was 600bps over Bell 103 Frequencies. 600bps was very challenging as the time and required me to design a "custom" demodulator and filtering system. The software running on the network protocol card was 1200 or so lines of embedded Pascal code with interrupt driven I/O.

Having developed and tested the outstation modem and network protocol card. I was invited to move the mining supply company to help integrate the network protocol card into their existing and planned outstations.

Huwood Electric LTD, Newcastle, UK

Microprocessor System Development Engineer, HEXATEC LTD, Hexham, UK  

Copyright Mike Wardley, 2011