Multichannel recorder for equidistant recording of significant changes of a measured variable in each channel

摘要

An apparatus for recording a plurality of variable analog signals individually and sequentially scanned during the recording operation. The analog signals are digitized, and the digital values multiplexed into a microprocessor which uses a stored program to determine significant changes in the scanned analog input and to store only meaningful data representing a significantly changed analog input in a buffer memory for subsequent recording on a recording chart. Specifically, the apparatus provides a selection of input values to be recorded whereat the recorded input values differ by a predetermined amount with respect to the measured value or the time basis of a recording chart. The buffer memory serves to match the velocities between scanning of the inputs and the printing of the measured variables since the inputs are scanned at a rate which is much higher than the print rate of the recorder to allow a follow-up of the measured variable which provides equidistant recording of the measured values.