Hardware and Software Interface of a Spectrophotometer System to a PDP-11 Digital Computer

The interfacing of a spectrophotometer with a digital computer is discussed. The spectrophotometer collects and measures spectral and environmental data from agricultural crops and products to estimate yield and disease. The wavelength position of the spectrophotometer is coupled to the interface through an electromechanical encoder. The output signal and the signal from the interface are applied to the direct memory access interface (DR11-B) of the PDP-11. The processing of the spectral data is accomplished by the software interface.