Merriam, Marshall & Bicknell
Monitoring system
 This disclosure deals with a system for monitoring the rate of operation of a cyclically operating machine or process or the rate of cyclically recurring events. The system monitors the rate by sensing each cycle occurring during a sampling time interval or duration and generating a signal which is taken as a standard value representing a standard rate. Either the length of time required for a specific number of events is measured, or the number of events occurring in a specified time is measured. The measured value is compared with the standard value and an indication is made of the comparison. 
G
G07C
inventional
Robert D. Robert W. James E.
Fisher Brandt Hill