A semi-automatic pen-recorder chart analyser
C W Spencer, G.H. Bazzard · Journal of Scientific Instruments · 1956
A description is given of an instrument which enables a rapid analysis of the variations of displacement of a pen trace upon a moving chart to be made. The pen trace is followed manually by means of a cursor making an electrical connexion with a number of fixed contacts, which are in turn connected through a distribution board to electrically-operated counters. A camoperated make-and-break switch produces the pulses to actuate any particular counter, determined by the position of the movable contact. The numbers of pulses recorded on the counters are measures of the amounts of time the pen displacement is between pre-selected levels across the chart.