Microprocessor Controlled Digital Period Meter

A microprocessor controlled digital period meter has been developed and tested operationally on a reactor at Argonne National Laboratory. The principal of operation is the mathematical relationship between asymptotic periods and pulse counting circuitry. This relationship is used to calculate and display the reactor periods over a range of ±1 second to ±999 seconds. The time interval required to update each measurement automatically varies from 8 seconds at the lowest counting rates to 2 seconds at higher counting rates. The paper will describe hardware and software design details and show the advantages of this type of Period Meter over the conventional circuits.