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AssigneeStorage Technology Corporation
InventorsBruce M. Davis, Steven S. Stetler, Chester L. Rebman
Estimating the term…
A system and method is provided for positioning a take-up reel in a tape drive unit so that a leader block can be inserted therein. The take-up reel is driven by a motor having a rotatable shaft and a motor controller. A position encoder, mounted on the shaft of the motor, uses a Hall-effect device to generate a Hall voltage signal in response to rotational motion of the motor shaft. The Hall voltage signal is amplified to provide a motor phase signal which is then compared to a reference level (usually zero volts) to generate encoder pulses. The encoder pulses are counted using a counter/state machine to determine a position and direction of rotation of the take-up reel. A feature of this system is that it is calibrated using a processor that determines the DC level of the motor phase signal and subsequently adjusts the motor phase signal so that it is substantially symmetrical about the reference level to which it is compared. The microprocessor accomplishes this by measuring a maximum and a minimum value for the motor phase signal, determining the offset about a DC level of the Hall voltage signal using these measured values, and generating a feedback signal to adjust the DC level of said motor phase signal as desired. This calibration is performed for a fixed period of time and only while the motor shaft is rotating. This ensures that actual maximum and minimum signal values are used for the calibration.
A system for positioning an object at a desired position, comprising:
A method of calibrating a system for determining the position of an object, the system having a position encoder device that provides a first signal having a DC component and an AC component, comprising the steps of:
A system for calibrating a position encoder device used for determining the position of an object, the position encoder device providing a first signal having a DC component and an AC component, the system comprising:
Dependencies are inferred from the claim text.