Process regulating circuitry using two measurers in parallel - has range selection stage cooperating with proportional member and lowest and highest value limiting stages

摘要

A controller receives a conrol parameter. A control element in the processing system is iregulated by the output of the controller. Two or more parallel measurement devices (21, 22) have different measurement ranges which intersect at one or more points. Each measurement device has an associated controller (2, 3) with control gain matching its transfer characteristic. The controller outputs are selected according to the control value relative to the intersection point. The characteristics of the control and/or feedback parameters can be varied. USE/ADVANTAGE - Accurately controlling processes with large control range, i.e. stipulated value variable to several powers of ten, with single processing line.