Sharp MZ-80SFD Bedienungsanleitung PDF herunterladen (Seite 4)

I OPERATIONAL PRINCIPLE OF FLOPPY DISK

1

The

floppy disk

is

designed

to

rotate

the

so-called

"diskette,"

a magnetic disk storage unit,

to

read

out

and write in data

at

high speeds

by

bringing the

magnetic head

in

direct

contact

with

a specified track

sector of

70 tracks formed in

both

surfaces

of

the

diskette.

1. Fundamental block diagram

Read

data

Read circu it

Operation

(}--:":":'"":".-----""'1'---------.

.

d'

Write

In

Icator

./

protect

. .gr

/'

senso!'-/

Indexr::;::?

Head select

Write

data

Write gate

Write

protect

Drive

select

Write circuit

«

,/

sen,s~JJJ'

.~~

~

Head load-

Write

protectr"'··"

.

actuator

la,*/'

.,

)'1

I

'--.---..----,

.......

Index

I!:;,'

1

. .

Head select Head load • •

__

s_t_e;..p

__

......

,.......L--L--~I-

____

~.

Rea1/write~"-

•

..".

Direction -

Index ,

head

~:I:

\t-='.INV1I1

Motor

ON

...........

Track

00

'.

...

..,;D~r;;;;iv;,;.e;..s;;;;el;,;.e-ct--f

Control

circuit

1-

__

-,

Diskette

Head select

Motor

ON

2. Mechanism explanation

This device consists mainly

of

the

following

mechanisms.

Motor

control

circuit

1)

Read/write head

41

0 iskette driving mechanism

The head

is

attached

to

the

arm

through

a leaf

spring.

The

head can follow

the

motion

of

diskette easily.

Signals read

out

of

the

head are

transmitted

through FPC (Flexible Printed Cable)

to

the

read

amp. circuit.

2) Carriage assembly

2 units of read/write head are

mounted

on

the

carriage. The carriage

is

located with

the

stepping

motor

and lead screw.

3)

Head locating mechanism

This

is

a high-precision, reliable head locating

mechanism using stepping

motor

and screw-driven

ball/V -groove system.

The

stepping

motor

is

of

7.5°/pulse, steel

plate

type.

One pulse of

step

signal causes a 2-step

rotation

by

15

0

,

thus pushing forward

the

head

by

one

track.

A small-sized

DC

motor

with tacho-generator

is

employed. The

motor

rotation

is

transmitted

through

the

drive belt, spindle pulley and spindle

hub, thereby causing

rotation

of

the

diskette. This

spindle pulley

is

provided with a stroboscope

to

check

rotation interval.

5) Head load mechanism

This

is

a mechanism in which

the

head

is

brought

into

contact

with

the

diskette. It

is

operated

by

the

head load actuator.

L..-

_________________________

._~

_____

~_.

______________

_

-2-

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