Soft Real-Time PID Control on a VME Computer

microPID (μPID) is a computer program for real-time proportional + integral + derivative (PID) control of a translation stage in a Fourier-transform ultraviolet spectrometer. μPID implements a PID control loop over a position profile at sampling rate of 8 kHz (sampling period 125 μs). The software runs in a stripped-down Linux operating system on a VersaModule Eurocard (VME) computer operating in real-time priority queue using an embedded controller, a 16-bit digital-to-analog converter (D/A) board, and a laser-positioning board (LPB).