Track Access Mechanism; Index Pulse - Fujitsu M255XK Customer Engineering Manual

2.4 TRACK ACCESS MECHANISM
Table 2-3 Track Access Mechanism
STEPS PER TRACK
1 step
ACCESS TIME
Track to Track 3 msec
(Without settling time)
Average (Inner-track)
94 msec
(With settling time)
POSITIONING ACCURACY
Within .:t 20 micrometers at 96 TPI (Track 32),
using a Standard Test Diskette at 74
0
F (23
0
C)
.:t20 at 40-60% Relative Humidity
HEAD SETTLING TIME 15 milliseconds maximum, does not include track
access time
HEAD CARRIAGE DRIVE
4-Phase Stepper Motor and Steel Belt
TRACK 00 DETECTION
LED and Photo-transistor Detection
Mechanical stop on head carriage
2.5 INDEX PULSE
Table 2-4 INDEX Pulse
INDEX DURATION
1 to 8 milliseconds (use the leading edge)
TIME BETWEEN INDEX 200.00 milliseconds .:t 1.5% at 300 RPM
PULSES 166.67 milliseconds .:t 1.5% at 360 RPM
INDEX ACCURACY 200.:t 150 microseconds from the beginning of
the INDEX hole on a standard test disket te
FIRST INDEX PULSE
400 millisecond nominal after Motor Start
NUMBER OF PULSES
One (1)
INDEX Pulse per disk revolution
INDEX DETECTION
LED and Photo-transistor
TS-021-013087 ••• 01
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