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MODEL 616
coded lines are used to generate the decimal point
drive .
The lines are designated R
Inverters QA404A , C , E provide a log c
a corresponding logic " 0 "
any of the lines.
When used in the AUTO mod e , a
fourth line
is used to defeat the automatic rang
ing circui t .
The remote enable line
vated when a connec tion to LO i s made at pin 6
on LSI OA40 B .
truth tahle for c!ecifTlsl point logic
A
i s given i n Table 4-6 .
TABLE 4-6 .
Decimal Point Coding
Sens i t ivity
Setting
. 0 1000
. 1000
1 . 000
10 . 0 0
100 . 0
d .
by diode network DN40 3 .
the c athod,es for segments A
When transistor Q403 is turned o f f , the display in
dicates a 11111 since segments B and
turned on (pins 10 and 13 are connected to LO) .
e .
range i s selected , the 616 display indicates a
f i f th d i g i t (DN40 2) and decimal p o i n t .
Q402 controls the cathodes for segments
t o disp'lay a 1 1 011 .
Transis tor Q402 is turned off
when R 4 is high (QA404A
f .
is controlled by trans istor
always lighted .
Additional
for the plus sign .
Overload Indication.
contains additional c i rcuitry for overload b lanking
of the display.
When the display exceeds 200 volts ,
the circuit causes a b linking action of the three
least signif icant digits .
up to 201 . 7 volts ( 0 0 1 . 7 max . ) .
4-6 .
OSC ILLATOR .
REFERENCE
(clock) circuit is composed of integrated circuit
QA406 and other fixed components forming a free
running oscillator.
The oscillator operates a t
frequency o f approx. 1 0 kHz.
tor Q 4 l l is a clock pulse between - 0 . 7 volt and +5
volts d c with a 5 microsecond pulse width.
4 - 7 .
MISCELLANEOUS C IRCUITS USED FOR 6 1 6 2 ,
circuits are used to generate signals or s i gnal
levels for the Model 6162 Isolated Output/Control.
a .
Gated Clock.
TIlis circuit i s composed o f in
verters QA40SD , E , F and NAND gates QA407A , B , C .
circuit combines s ignals from the L S I module and
clock to provide a gated clock IIGC " .
"eN" are used to generate BCD outputs in the Model
6 16 2 .
1175
Three
i
' R
4
s t a t e f o r
state (closure t o LO) on
(MR)
is acti
R
R
"1
4
2
0
X
X
0
1
0
1
0
1
1
1
0
1
1
1
Over range is indicated
Trans i s t o r Q403 controls
to display a "0 ·· .
, D , F ,E
are always
C
When the 10 millivolt
Trans istor
A , B , C , D , F , E
low) .
=
The polarity display DN401
Q401.
The minus sign i s
segments are turned on
The LS� module (QA408)
Tae d i s p lay reads properly
The reference frequency .
The output of transis
These
This s ignal and
h .
Decimal Point.
inverter s t ages QA40SA , B , C which provide sufficient
'
drive for optical isolators in the Model 6 16 2 .
cimal point is coded in three lines R 4 , R 2 ' R l as
shown in Table
(MR)
4-8 .
POWER SUPPLIES ( S chemat i c 25777D) .
a .
over two ranges of line voltage .
two line voltage positions as follows :
117V:
90V - 125V rms range
234V:
l80V - 250V rms range
Fuse (F20l) mus t be selected for each line voltage
range as f ollows :
117V :
234V:
h .
Secondary Powe r .
is composed of four separate supplies .
T20l provides four center-tapped secondary windings .
1 .
± 2 75V Unregulated .
power from secondary windings 1-2-3 of T20l.
D20l through D204 form voltage-doubling supplies .
Output voltage is approximately 275 volts at 2
milliamperes (at nominal line voltage ) .
approximately 2 volts peak - to-peak at no load .
2 .
± 12V Regulat e d .
from secondary windings 6 - 7-8 of TZOI .
a four - diode ful l-wave bridge.
QA201 provides a regulated ±12 volts a t 10 milli
amperes.
peak-to-peak a t nominal loading .
- 9V Regula ted .
3 . .
D20 S for full-wave rectification.
D206 provides a regulated voltage of -9V at 5
milliamperes .
volts peak-to-peak .
4 .
+5V Regula ted.
from secondary windings 9-10 - 11 of T20 1 .
DZ07 and DZOB form a ful l-wave rectifier.
grated circuit QA203 provides a regulated output
of +5 volts at ZOO milliamperes .
I
imately
5 .
+lOV Unregulate d .
unregulated output of the f u ll-wave rectifier D207-
Ripple is approximately 1 volt peak - to - peak
DZOB.
at 200 milliampere loading .
6 .
-lZV Regulated .
from secondary windings 13-14-15 of TZO I .
D209 and D2l0 form a full - wave r e c t i f i e r .
The
grated circuit
Trans istor Q20l is a series - pass regula tor .
put voltage is -12V at 50 milliamperes .
is approximately 2 millivolts peak-to - peak .
THEORY OF OPERATION
This circuit i s composed of
4 - 6 .
}
The Model 616 can be operated
Switch S20l has
50-60 H
3/16 ampere, 3AG SLO - BLO
1/10 ampere, 3AG SLO - BLO
The Model 616 power supply
This supply taps a-c
This supply taps u - c power
Integrated circuit
Ripple i s approximately 1 millivolt
This supply also u t i l i zes
Ripple is approximately 3 milli
This supply taps a- c power
millivolt peak - to-peak.
This supply u t i l i zes the
This supply taps a-c power
i s a regulator element .
QA202
De
z ,
9
W
Transformer
Diodes
Ripple is
D205 i s
Zener diode
Diodes
Inte
Ripple is approx
Diodes
Inte
Out
Ripple
2 7
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