Patent ID: 7512460

Claim:
A method for calibrating a proportional solenoid valve operable for controlling a device for changing a displacement, comprising steps of: providing a proportional solenoid controlled valve, the valve including a supply pressure port, at least one work port, and a tank port, the valve being controllably operable responsive to a control signal input for moving through a predetermined range of positions, including a range of positions wherein hydraulic fluid will be directed through the valve between at least the supply pressure port and the at least one work port; providing a hydraulic cylinder in fluid communication with the at least one work port, the hydraulic cylinder being operable to move an element to various positions within a range of positions responsive to delivery of hydraulic fluid thereto from the at least one work port; providing a sensor operable for detecting displacements of the element and outputting displacement signals including information representative of detected displacements; providing a programmable control module in connection with the valve and the sensor, the control module being operable for outputting control signals to the valve and receiving the displacement signals from the sensor; and wherein the control module is programmed for automatically calibrating the control signals, including steps of: i. outputting a test control signal having a predetermined value to the valve for causing a predetermined displacement of the element, and comparing information representative of an actual displacement caused by the test control signal to information representative of the predetermined displacement; ii. if the actual displacement is greater than the predetermined displacement, then incrementing a first counter and calculating a new test control signal as an average of the predetermined value of the test control signal and a first predetermined value; and iii. if the actual displacement is less than the predetermined displacement, then incrementing a second counter and calculating a new test control signal as an average of the predetermined value of the test control signal and a second predetermined value, and iv. repeating steps i through iii a predetermined number of times; storing the value for the test control signal; and operating the hydraulic cylinder using the stored value for determining displacements of the element.