Honeywell International Inc.
Detection of loop resistance and leakage current in input/output (I/O) loop

Abstract:

A method includes obtaining different measurements of voltages across terminals of a field device coupled to an I/O loop. The voltage measurements are associated with corresponding loop currents flowing through the I/O loop. The method also includes identifying a baseline loop resistance measurement of the I/O loop using the voltage measurements and the loop currents. The method further includes obtaining additional measurements of voltages across the terminals of the field device. The additional voltage measurements are associated with additional corresponding loop currents flowing through the I/O loop. The method also includes identifying additional loop resistance measurements of the I/O loop using the additional voltage measurements and the additional loop currents. In addition, the method includes detecting a problem with the I/O loop based on the baseline loop resistance measurement and the additional loop resistance measurements.