DUST COVER
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 u m . Logic
f alse (high) is + 2 .4 volts mini m u m .
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.
INPUT CONTROL LINES
COOLING
T hese input l i nes are indi v i d u a ll y t e r m i n a t e d
t hrough a 150 ohm r e sistor pack i n s t 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 te d c i r c u i t
location RP5 (or RP1 in th e L a rge Scale Int e-
gration version). In a single-drive system, this
r esistor pack s h o ul d b e i n s t a l le d t o p r o v i d e
t he proper t e r m i n a t i o ns. I n a m u l t i p l e -dri v e
system, only th e l ast d r iv e on th e 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 driv e can t e r m i n at e t h e f o l l o w in g i n p u t
lines:
H eat d i ssipation f r o m a s i n g l e d r i v e i s n o r -
mally 20 w a t t s, 68 BT U per h o ur, under hi gh
load conditions. When the drive is
mounted so
the components have access to a
free flow of
air, norma l c o n vection cooling a l l ow s 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 aintai n s p ecified a i r t e m p e r a t u re s i n t h e
vicinity o f t h e m o t ors, pri n ted cir cuit h o ards,
and diskettes.
W hen f o r ced ai r i s u s e d , a i 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
nr h e a d s a n d
diskettes.
1. D i r e cti on
2. St ep
3 . W r i t e D a t a
4. W r i t e Gat e
5 . I n U s e
6. Side Select (TM848-2E only)
7. W r i t e Curr ent Swit ch
8. H ead Load
3.4 INTERFACE CON N E C T IONS
M O TOR ON CON T R O L
I nterface connections for t h e T M 8 4 8 -1E a n d
T M848-2E are made via a user-supplied, fif t y -
pin, flat
ribbon connector, 3M Scotchflex, Part
Number 3415, or it s equiv alent. Thi s 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 i n t e r f ace description o f t h e c o n n ectors,
and the l ocation of e ach one, is contained i n
t his section . I n t e r f ac e l i n e s a r e l o c a te d i n
Table 3-1. D. C. power connector pi n a s sign-
ments are located in T a bl e 3-2, Section 3.5 of
this manual.
T he signal w i r e h a r n ess should be of th e fl a t
r ibbon or t w i s ted pair t y pe, have a max i m u m
length of ten feet,
and have a 26-to-28 gauge
conductor compatible wit h th e connector to be
u sed. It i s r e c o m m ended t h a t t h e i n t e r f a c e
cable have a characteristic i m p edance of 100
ohms.
DRIVE SELECT LINES
The Motor On Control li nes are used to control
t he spindle m o t or. W i t h t h e M O L j u m p e r i n
( factory install ed), the Motor On Control l i n es
are low tr ue. Wit h t h e M O H j u m p er i n s t a l l ed
( optional), t h e M o t o r O n C o n t r o l l i n e s a r e
high true (see Table 3-3 located in Section 3.6).
T he D r i v 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 . T h ese four
lines, DS 1 t h r o ug h D S 4 , a l l o w i n d e pendent
selection of up to four drives attached to the
controller.
W hen the signal l o gic l evel i s t r u e ( l o w), t h e
d rive electronics are acti v at ed, and th e d r i v e
is conditioned to respond to Step or to Read/
3-2
