Patent ID: 8032328
Filing Date: 2011-10-04
Classification: G05B

Abstract:
1. A periodic or intermittent chemical process monitoring method comprising a) obtaining at least one input process variable; b) determining a comparative process value based on at least one input process variable using a first method having a first time-based weighting function; c) determining an expected process value based on the at least one input process variable using a second method having a second time-based weighting function; d) determining a first deviation value based on the at least one input process variable or historical data; e) calculating a limit range having a maximum limit and a minimum limit using the expected process value and the first deviation value; and f) comparing the comparative process value to the limit range, wherein the at least one input process variable is temperature, pressure, voltage, flow, weight, switch position, current, power, height, frequency, model prediction error, concentration or physical product property measurement; and wherein at least one of steps a), b), c), d), e) or f) is accomplished using a computer system.