electronic circuit design was completed first. The earlier consultation
and preparation of the subsequent proposal had identified many
of the components required by the detailed design. When completed,
the electrical design was reviewed with the customer to ensure
it met their original criteria. On approval the design was committed
to a circuit board. This stage took into account the size and
shape of the enclosure to be used for the operators console,
to ensure the two parts would fit together later. Detailed design
of the mechanical enclosure, including the safety cover, followed.
As each component was finalised it was issued for manufacture,
thus minimising delays in the whole project.
With all the hardware design complete attention now turned to the
software. This software was split into two parts. The first was the
embedded control programme for the microcontroller that resides in
the test console, the second part was the PC based user interface.
Both programmes were written in a high level language, namely C. The
two programmes communicate with each other through a RS-232 serial
The Embedded Software
This was designed to respond to simple text commands by performing
operations like switching a relay or making a single voltage measurement.
This simplicity made both hardware and embedded software testing quick
and easy, as all of the equipments basic functions could be
verified as working correctly by using just a dumb terminal. Having
established that the test station was fully operational we could now
write and test the automatic control program for the host PC.
The PC Host Software
main purpose of the PC host software is to perform the actual
testing. The program was designed to run under DOS, and used
Boa Systems own proprietary windowed environment. All operator
input is provided via the keyboard.
The software is capable of running without the actual test
station being present so that tests specifications could be
created and test results extracted on any available PC.