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OPERATION
2.
1 VOLT OlJTPLn.
This output
provides
a I vole
analog
output
corresponding
to a full
range
input.
The 1 VOLT OOTPW is useful
for monitoring
by oscil-
loscopes
or voltmeters
which will
not
load the ELec-
trometer
output
to exceed
0.1 microamperes.
This
output
is also
used for calibration
of the analag-
to-digital
converter.
a.
General
3.
X1 OUTPUT (unity
Cain).
This output
provides
a unity
gain
signal
for applications
requiring
very
accurate
measurements
from high
impedance
sources.
The output
is equal
to input
within
100 ppm at dc,
exclusive
of noise
and zero drift,
for output
cur--
rents
of 100 microamperes
or lees.
1.
The Model 615 has provision
for
the installa-
tion
of output
buffer
printed
circuit
boards
co ob-
tein
Sinary
Coded Decimal
(RCD) outputs.
Two !+!a-
pin card-edge
connectors
are installed
and complece-
ly wired
on the main PC board.
4.
DIGITAL OuTPLm.
refer
to Paragraph
2-10 for
a complete
description
of the PRINTER/CONTROL con-
nector
and external
controls.
2.
A factory-wired
50-pin
PRINTER/CONTROL cannec-
tar
is also
provided
on the rear
panel.
Thik con-
nector
is wired
to provide
signals
as described
in
Table
8.
This
Amphenol (RLue Ribbon Series)
connec-
tar can be ordered
with
special
wiring
configure-
tions.
b.
Use of the Xl Output
(Unity
Gain)
1.
normal
"ode ?.,eaeureme,,ts.
a)
Connect
the Electrometer
to the unknown volc-
age source
as described
in Paragraph
2-4,
d for
normal Mode voltage
measuremeots.
3.
Output
buffer
cards
available
from Keithley
as Model 4401 Printer
Output
Cards.
may be ordered
factory
installed
or ordered
at a later
date
for
user installation,
since
no soldering
or rewiring
is required.
These Output
Cards are available
with
other
codes (Standard
Code is l-2-4-8)
on a CIISC~I
design
basis.
4.
Accessories
b)
Connect an *ccuraLe
voltmeter
such as a
a)
Model 4401 Printer
Output
Cards.
include
two
0.01% differeneial
voltmeter
between
the X1 Output
buffer
output
cards
and a mating
Amphenol connec-
and the GUARD Terminal
as shown in Figure
7.
tor.
c)
Adjust
the Model 615 ZERO Control
to obtain
a null
reading
on the differential
voltmeter
with
the ZERO CHECK Switch
in LOCK position.
b)
A fifty
line
cable
for hook-up
to external
devices
(printers,
computers,
etc.)
is avaiLable.
Specify
part
number SC-51 and length
desired.
2.
Fast Mode MeasuremenLs
b.
Output
Codes and Levels.
a)
Connecr the Electrometer
to the unknown volt-
age source
ee described
in Paragraph
2-4,
e for
Fast Mode voltage
measucements.
1.
me PRINTER/CONTROL outputs
are i3inary
Coded
Oecimsl
(SCO) signals
with
l-2-4-8
Standard
code.
b)
Connect
a recorder
or oscilloscope
between
the x1 Output
and the GUARD Terminal.
In the FAST
Mode, the XI Output
Terminal
is connected
to input
low.
The GUARD Terminal
provides
an output
for
recording
purposes.
2.
The Standard
signsl
levels
are as follows:
Logic
"0"
< co.4 volt
Logic
"1"
> *lO volts
at up to 1 milliampere.
-
FIcUwi
7.
Use of xl Output
for Measurement
from a High Resistance
Source.
0470
I 3
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