Method for simultaneous reference junction compensation of a plurality

Abstract

A method for simultaneous compensation of a plurality of thermocouple signals where the thermocouple leads are terminated to dissimilar metals without using individual ice junctions for compensation of each thermocouple signal is disclosed. The thermocouple leads are all terminated to individual connectors as reference junctions which are held at the same temperature by a block of metal which stabilizes thermally with its environment. The temperature of the metal block is measured by an integrated circuit temperature transducer which produces an analog electrical signal proportional to the temperature detected. This signal is digitized and a microprocessor calculates the temperature of the metal block which is placed on a first data bus. Additional microprocessors are connected to the individual thermocouple leads. These microprocessors convert the thermocouple signals into an uncorrected digital temperature. The microprocessors read the temperature of the metal block from the data bus, adds this temperature to the digitized thermocouple temperature signal, retransmits the corrected digitized temperature signal on a second data bus to a central computer, converts the corrected digital temperature signal to an analog signal and transmits this signal to external devices.