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Fujitsu MHV2040AH, MHV2100AH, MHV2060AH, MHV2080AH manual Self-calibration contents

Models: MHV2040AH MHV2080AH MHV2060AH MHV2100AH

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4.5 Self-calibration

4.5 Self-calibration

The disk drive occasionally performs self-calibration in order to sense and calibrate mechanical external forces on the actuator, and VCM torque. This enables precise seek and read/write operations.

4.5.1 Self-calibration contents

(1) Sensing and compensating for external forces

The actuator suffers from torque due to the FPC forces and winds accompanying disk revolution. The torque varies with the disk drive and the cylinder where the head is positioned. To execute stable fast seek operations, external forces are occasionally sensed.

The firmware of the drive measures and stores the force (value of the actuator motor drive current) that balances the torque for stopping head stably. This includes the current offset in the power amplifier circuit and DAC system.

The forces are compensated by adding the measured value to the specified current value to the power amplifier. This makes the stable servo control.

To compensate torque varying by the cylinder, the disk is divided into 13 areas from the innermost to the outermost circumference and the compensating value is measured at the measuring cylinder on each area at factory calibration. The measured values are stored in the SA cylinder. In the self-calibration, the compensating value is updated using the value in the SA cylinder.

(2) Compensating open loop gain

Torque constant value of the VCM has dispersion for each drive, and varies depending on the cylinder that the head is positioned. To realize the high speed seek operation, the value that compensates torque constant value change and loop gain change of the whole servo system due to temperature change is measured and stored.

For sensing, the firmware mixes the disturbance signal to the position signal at the state that the head is positioned to any cylinder. The firmware calculates the loop gain from the position signal and stores the compensation value against to the target gain as ratio.

For compensating, the direction current value to the power amplifier is multiplied by the compensation value. By this compensation, loop gain becomes constant value and the stable servo control is realized.

To compensate torque constant value change depending on cylinder, whole cylinders from most inner to most outer cylinder are divided into 13 partitions at calibration in the factory, and the compensation data is measured for representative cylinder of each partition. This measured value is stored in the SA area. The compensation value at self-calibration is calculated using the value in the SA area.

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Page 63
Image 63
Fujitsu MHV2040AH, MHV2100AH, MHV2060AH, MHV2080AH manual Self-calibration contents
Page 62 Page 64

MHV2040AH, MHV2080AH, MHV2060AH, MHV2100AH specifications

The Fujitsu MHV series of hard disk drives, specifically the MHV2060AH, MHV2080AH, MHV2100AH, and MHV2040AH, are renowned for their reliability and performance in the mobile HDD segment. Designed primarily for use in laptops and other portable devices, these drives integrate cutting-edge technologies to meet the demands of today's data-intensive applications.

One of the hallmark features of the MHV series is its high data density, allowing for substantial storage capabilities in compact sizes. The MHV2060AH offers a storage capacity of 60 GB, while the MHV2080AH and MHV2100AH offer 80 GB and 100 GB respectively. The MHV2040AH provides a slightly more modest but still robust 40 GB of storage. This range of capacities ensures that users can select the model that best fits their storage needs.

The drives utilize the latest perpendicular magnetic recording (PMR) technology, which enhances recording efficiency and increases data storage densities. This technology significantly optimizes the use of disk surface area, providing better performance and more reliable data access. Additionally, the MHV series incorporates an advanced actuator system that ensures precision head positioning, enhancing data integrity and reducing error rates during read and write operations.

In terms of performance, the MHV series maintains a revolutions per minute (RPM) rating of 5400, which strikes a balance between speed and energy efficiency, making these drives suitable for low-power applications. The drives are also designed with a low acoustic level, generating minimal noise during operation—a crucial factor for mobile users who prefer quieter devices.

Furthermore, the Fujitsu MHV series features a robust shock resistance design, allowing them to withstand the rigors of mobile computing. This makes them suitable for use in portable environments subject to vibration and physical movement, thus ensuring data security and drive longevity.

Overall, the Fujitsu MHV2060AH, MHV2080AH, MHV2100AH, and MHV2040AH represent a formidable selection of mobile hard disk drives filled with advanced technologies and features, making them well-suited for a wide range of applications in today's fast-paced digital world. With their combination of storage capacity, performance, and durability, these drives continue to serve as reliable solutions for users seeking efficient data storage in portable formats.