LFE 2000 Series - Page 40

958_31
REV.
B
1.8
ry!prtrc4!lllN
rB_Or't_THERMOc_ou_pLE
rNprjr
r0
BRTDGE
lg4NprJCI&
urUI
Thrs
modjfrcation
provides
a
separate
regulated
ancl
isolatecl
power
supply to
produce
excrtation
for
an
external
4-wlre
brtdge
transducer.
The
power
supply
pCB
and othel'
parts
rteeded
to
riake
this
modif
ication
are
contained
in
either
of two krt-s: l82l-l l9
for
5 VDC
at
50
mA
rrax
or
l82l-120
for
10
VDC
at 100 mA max
(some
other
voltages;rre
avat
Iabl e
-
check
thet
f actory
f or
inf ornration)
.
If intermediate
or hrgtrer
powpr
supply
voltages
are
speclf
red
by
the t r;rnsducer
manuf
acturer',
rrse the
5V
strpply
f ot'
rat
l llgs
between
5
and
10
V
or use
the 10V
supply
f or ratings
over
lOV. Wherr
u.sirrg
trarrsducet's
at
lower
srrpply
voltage.s
than recommended,
scale
the
br
rdte output
back
t'n the
same
ratro
as
the
actual
vs rated
supply
voltages.
Make srrre that the
ctrrrent
drawtr
by
tlre t
ransducer
does
not erceed
the
power
supp 1y
maxrmum rilr r nt.
'l'ht
s
nrodrf
-icatloll
Inay
not
be
adcled
to controllers
wrth
cl rgital
comfllrlrrtc;1t lolllr,
irrprrt
(rr
analog
output
tsolation
or
rernote
start/stop
optiolt.
Because
extr;t
ternrinals
are
reqrrrred
t.rr connect.
tl're
povJer
supply
r)utl)ut
to the
erterrral
transdllcer,
it
is
necessary
to
rest.rict the
number ol option;rl
olltpqts.
Thls
instlrrct
jon
assumes
that
the secondary
output
is t-rot supplied. tlther
ararlgelnellts
sttch
as
usf
ng
the ALARM2 t.et'rninals
f
or
the
powcll
supply
oltr.put
,-ti e
possrbl
t,
but rrot
covered
by
thrs
instruct ion.
Remove
t-he
Input
/Output
(I
lO)
boarcl
f ronr the
electrorric
asserrrbly
and the
Mother boai
rl
f r-onr
the
he,ze-7
assembly per
irrstnrction
in Sections
1.8 and I.10
anrl nrake the
followrng
changes.
(l,FE
p/N's
in brackets.
)
ADD
cerrt.er-board
connector-Pl
(J45-764)
to
Mother board
(not.
rreeded
if
rrrrrt
al teady
has
center
board
connector
installed).
,)
SOI,DER
the
st ripped
end
(2)79-197).
of
the black
lead
assembly
rn tIPIT bo;ri-d
hole Al5
5.
4.
5.
b.
7.
t.
S0t
DF.R the
strrpped
end
of
the black/white
leacl assernbly
in
Alb
(237')-276\.
C Ptl hoa
rd
ho
I
r:
S()I,DER
ttre
stri.pped
end
of
the
green
I ead assembly
rn
Cpll ho;rr<l
hrrlr,
.A l7
(
237',1-201
| .
DETERMINIi
the
approximate
transducer
output
at
tl-re
;lppl
ied
powpr
strpply
voltage.
R;rnge
the
input
cjrcujt
according
to Sect
ion 1.4 or 1.5.
INSERT
po\ter
srrpply
boaril
(srrpplrrrd
in kit l82l-
Il9 oi krt
1821-120)jn
rtre,
ceritcr
boai'd
corrrrect-ot-.
c0NNECT
the
black
le;rd
fronr
the cPlJ bcrarcl
to center board
prn
Al.
thr-'bl;,rck/wlrite
learl
frorn
the cF'U board
t-o cent.er
board
pin
A2.
the
greerr
l e;rd
f
ron the
IIPIJ
board to
cerrt,er board
pin
Al.
U0NNEC I
the
i ed lead
f r-on:
the
center board to
I
/0
board
prn
black
lead
frctnr t-he
cpntpr
board
to
I/tJ board
pin
A!.
C(INN I,]CT
(:IJ
NN F,(]1'
ASSEMBLE
rear
errds
of PCBts
totether
usint new
shorter spacel-s
suppl
red
tn the krt.
(
see
Figuie 1-l
)
A7
;rrtd the
;rnd h,:r rdwa i'e
9.
-33-
t,FF, Irrstru:lents
Dtv-t s t
r-rrr