General-purpose stepping motor-encoder positioning subsystem with standard asychronous serial-line interface

A general purpose mechanical positioning subsystem for open loop control of experiment devices which have their positions established and read out by stepping motor encoder combinations was developed. The subsystem is used mainly for experiments conducted at the National Synchrotron Light Source. The subsystem unit was designed to be compatible with a wide variety of stepping motor and encoder types. The unit is operated by any device capable of driving a standard RS-232-C asynchronous serial communication line. An informal survey has shown that several experiments at the Light Source will use one particular type of computer, operating system, and programming language. Accordingly, a library of subroutines compatible with this combination of computer system elements was written to facilitate driving the positioning subsystem unit.