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DUST COVER
The design of an enclosure should incorporate
a means to prevent contamination from loose
items, e.g., dust, lint, and paper chad since the
drive does not have a dust cover.
COOLING
H eat dissipation f r o m a
mally 20 w a t ts, 68 BT U per hour, under high
load conditions. When the drive is mounted so
the components have access to a free flow of
air, normal c o nvection cooling a l l ows opera-
tion within the specified temperature range.
W hen t h e
d r i v e i s m o u n t e d i n a co n f i n e d
environment, air flow must be provided to
m aintain s p ecified a i r t e m p e r a t u res i n t h e
vicinity of t h e m o t ors, printed circuit hoards,
and diskettes.
W hen f o r ced ai r
i s u s ed , ai r fl o w m u s t b e
directed outward from the drive. Do not
intake
ai r t h r o u gh t h e d r i v e
diskettes.
3.4 INTERFACE CONNECTIONS
I nterface connections for t h e T M 8 4 8 -1E an d
T M848-2E are made via a user-supplied, fift y -
pin, flat ribbon connector, 3M Scotchflex, Part
Number 3415, or it s equivalent. This connec-
t or m a t e s d i r e c tl y w i t h t he ci r c u i t b o a r d
connector at the rear of the drive.
The in t e r f ace description o f
and the location of each one, is contained in
t his section. I n t e r f ace l i n e s a r e l o c a ted i n
Table 3-1. D. C. power connector pi n a ssign-
ments are located in T a ble 3-2, Section 3.5 of
this manual.
T he signal w ir e h a r ness should be of th e fl a t
r ibbon or t w i sted pair t y pe, have a maxi m u m
length of ten feet, and have a 26-to-28 gauge
conductor compatible with th e connector to be
u sed. It
i s r e c o mmended t h a t t h e i n t e r f a c e
cable have a characteristic i m pedance of 100
ohms.
s i n g l e d r i v e i s n o r -
nr h e a ds a n d
t h e c o n n ectors,
A ll i n t e r f ac e s i g n al s a r e T T L c o m p a t i b l e .
Logic true (low) is + 0 . 4 volt m a x i m um . Logic
f alse (high) is + 2.4 volts mini m u m .
INPUT CONTROL LINES
These input l i nes are indivi dually t e r m i n a t ed
t hrough a 150 ohm r e sistor pack i n st a l led i n
t he di p s o cket l o c ated a t i n t e g r a ted c i r c u i t
location RP5 (or RP1 in th e L a rge Scale Inte-
gration version). In a single-drive system, this
r esistor pack s h oul d b e
t he proper t e r m i n a t i ons. In a
system, only the last dr iv e on the i n t e r f ace is
to be terminated. All other drives on the inter-
face must have the resistor pack removed.
T he drive can t e r m i n at e th e f o l l ow in g i n p u t
lines:
1. Di r e ction
2. St ep
3. W r i t e Dat a
4. W r i t e Gate
5 . I n U s e
6. Side Select (TM848-2E only)
7. W r i t e Current Switch
8. H ead Load
M OTOR ON CONTRO L
The Motor On Control lines are used to control
t he spindle m otor. W it h t h e M O L j u m p e r i n
(factory installed), the Motor On Control li n es
are low true. Wit h t h e MO H j u m per i n st a l l ed
( optional), t h e
high true (see Table 3-3 located in Section 3.6).
DRIVE SELECT LINES
T he Dr iv e S e l ect l i n e s p r o v id e a m e a n s o f
selecting and deselecting a d r i v e . These four
lines, DS1 t h r o ug h
selection of up to four drives attached to the
controller.
W hen the signal l o gic l evel is t r u e ( l ow), th e
d rive electronics are activ ated, and th e dr i v e
is conditioned to respond to Step or to Read/
3-2
i n s t a l led t o p r o v i d e
m u l t i p l e -driv e
M o t o r O n C o n t r o l l i n e s a r e
D S 4 , a l l o w i n d e pendent
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