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Introduction
System Structure
Spinstand System
HLM Stage, Spindle Stage
The HLM and Spindle stages simulate the head movement inside the disk drive. Both
stages employ the air stage. The air stage floats over the granite bed by means of
compressed air. And vacuum air is used to lock down the stages to the granite bed.
Piezo (HLM) Stage
When you make a track profile measurement it requires an extremely small amount of head
movement. To achieve such movement, a piezo element is employed.
The piezo stage is consisted of two main parts, namely; the actuator and flexure stage. The
piezo actuator is composed of a piezoelectric material that when voltage is applied to this
material it expands. The movement is controlled by applied voltage. E5035A/B controls
the voltage.
HLM (Head Loading Mechanism)
The HLM performs the loading and unloading of the HGA cassette. It has four photo
couplers, two of them are located inside of HLM in order to detect the HLM "load",
"unload" position. The other two are located beside the HGA cassette to detect the "up",
"down" position of the HGA cassette.
In the event that air or power supply is shut, the HLM will automatically unload to protect
the head and media from crashing.
Spindle
The spindle together with the stage employs an air spindle.Through air pressure the central
axis is caused to float, rotation is made by the motor. Clamp the head before rotation and
un clamp the head when it is stopped. Also, the spindle is equipped with a shroud as a
means of protection. If the lid cover of the shroud is open the spindle will not rotate.
Spinstand Controller
The spinstand controller is a component of the spinstand that controls every movement of
the spinstand except the HLM stage. The two main functions of the spinstand controller are
production of control signal and acquisition of status. It has four main components,
namely: controller, servo amplifiers, piggyback board and a power unit.
Control (PC) System
The commands for each measuring instrument and spinstand all come from the PC. The
commands being sent by the PC to each module of the VXI mainframe passes through the
IEEE-1394 interface. The triggers synchronizing with the index signal are generated from
Agilent E5035A/B Spinstand Interface Module to all modules and instrument. The Agilent
E5037A/B/C/D Data Generator Module sends its write data as controlled by the Write Gate
to the head amp from Agilent E5035A/B Spinstand Interface Module.
The same procedure applies for piezo, HLM and head amp. The command passes through
the Agilent E5035A/B Spinstand Interface Module.
The box type measuring instrument such as Oscilloscope and (4395A) are controlled by the
PC through GPIB cable. Also, the trigger to start measurement from Agilent E5035A
Spinstand Interface Module are received to start measurement.
Chapter 1
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