Delco

Design and implement a control and instrumentation system to operate and test a specialized switch. There is to be two nests each of which will contain two switches under test. One nest will be under test while the other nest is being unloaded and reloaded. The switches will need to be actuated in one direction and then in the reverse direction and distance to actuation and release must be measured and displayed to the operator.

A single board computer with a 6502 microprocessor was selected because of cost and availability of the product. Two motors, two displacement transducers, and one digital readout were also integral to the design. The software to exercise the two motors, measure the travel and display the results was written in 6502 assembly language and ROMed into the test hardware. The motor was run until max limit was reached or the switch had changed state. A decision was made and stored as to acceptance or failure on each switch in each direction. When both forward and reverse travel was accomplished, the pass/fail light for each switch indicated its condition.

The efficiency and accuracy of this test stand was realized immediately and three more of these tester were fabricated.

6502 based single board computer
DC motors
Displacement transducers
LED digital readout