Patent ID: 7104763

Claim:
A method for determining operating conditions in a medical pump having a cassette with a pumping chamber, comprising: monitoring the pump cycle with a position sensor; starting a testing timer for a pre-determined test time at a specified portion of the pump cycle; closing the pumping chamber to flow during at least a portion of the specified portion of the pump cycle; acquiring a plurality of pressure reference values during a first portion of test time from a single pressure sensor; calculating and storing a pressure anchor value by averaging the reference values; acquiring a pressure data value from the pressure sensor; calculating and storing a resultant value by subtracting the anchor value from the data value repeating the steps of acquiring the pressure data value and calculating and storing the resultant value until the pre-determined test time has expired; calculating a test value by averaging the resultant values; and comparing the test value with pre-determined threshold value to determine the operating condition of the pump.