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PERFORMANCE
VERIFICATION
WARNING
The
maximum
common-mode
input
voltage
(the
voltage
between
input
low and
chassis
ground
is 30V. Exceeding
this value
may create
a shock
hazard.
Some
of the
following
pro-
cedures
may expose
you to dangerous
voltages.
Use standard
safety
precautions
when
such
dangerous
voltages
are encountered.
CAUTION
The
maximum
voltage
between
the high
and
low input
terminals
is 250V
peak.
Instrument
damage
may occur
if this
value
is exceeded.
1. Connect the channel being verified to the DC calibrator
as discussed in paragraph 5.5.
2.For two-channel
units,
select channel
NOT being
verified and press SGLICONT. Do not press TRIGGER.
3. Select the channel being verified with the CHANNEL
button.
4. Program
the following
operating
modes with
the
associated front panel buttons:
A. Samples 10,000
B. Rate 10~s~
C. Coupling:
DC
D. Function:
average
E. Trirrer:
continuous
Y Y
5. Select the 32OmV range by using the Downrange
but-
ton. Press TRIGGER.
6. Program the calibrator output to O.OOOOV and place the
unit in operate. Press the Model 194 ZERO button to
enable the zero mode. Leave zero enabled for subse-
quent measurements.
7. Select the 1OV (or similar) range on the calibrator and
set the calibrator output to exactly 32O.OOOmV. Verify that
the Model 194 reading is within the limits stated in the
first line of Table 5-2 under the &bit
mode heading.
8. Select the next range listed in Table 5-2 and verify that
the reading is within
the stated limits.
9. Repeat this procedure for the remaining
ranges listed
in the table. Always use the lowest possible calibrator
range for the selected calibrator voltage.
10. Repeat steps 4 through
8 for voltages with negative
polarity.
11. Program
a 9.9,~~
sampling
interval
dnd
101,102
samples; repeat the above procedure.
Use the limits
stated in Table 5-2 for the R-bit mode.
12. If the Model 1944 option is installed
i" the channel 2
location,
repeat steps 1 through
10 for that channel.
Naturally,
you should use the channel 2 VOLTAGE IN-
PUT jack for the calibrator voltage input.
5.7 COMPUTERIZED
VERIFICATION
The following
paragraphs contain example progr""x
ior
performing the verification pnxxzdurc o" a semi-automated
basis. All the necessary programming
steps to control the
Model 194 for both 8.bit and lh-bit mode verification
JW
included in these programs. Steps necessa~ TV control the
DC calibrator are not included
becawe of the vari.ltion
i"
programming
languages
anwng
such
instruments.
However, program modifications
should be fairly simple
it1 most cases, depending
on the cwmplexity
of the
calibrator. Consult
the calibrator
instruction
~~x~nu~~l fw
details.
In each of the following
programs, the operator will be
prompted to apply the correct calibration voltage at the ,,p-
propriate point in the procedure and the" press J key tn
continue.
The program will obtain a reading
from the
Model 794 and then compare that readi"
to limits CIU~-
tained in program data statements. If the instrumwlt
is out
of specifications
at any point, the operator will be notified
of that fact by an appropriate
message on the computer
CRT.
Table
5-2.
Performance
Verification
Limits
Verification
Allowable
Reading (l8-28°C)
Range
Voltage
16-Bit'
E-Bit+'
320 mv
320.00 mv
319.70
to 320.30
mv
316.10
to 323.90
mV
3.2 V
3.2OOOV
3.1972 to
3.2028 V
3.1610 to
3.2390 V
32
V
32.000 V
31.969 to 32.031
V
31.670 to 32.390
V
200
v
200.00 v
199.73
to 200.27
V
196.6
to 203.4
V
*Sampling
rates c100kHz
and number of samples ~32,768.
**Sampling
rates >lOOkHz or number of samples >32,768.
5-3
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