Model 6517B Electrometer Reference Manual
Section 16: Verification procedure
6517B-901-01 Rev. C / August 2015
16-13
Calculating ohms reading limits
Ohms reading limits must be calculated from the actual standard resistance value and the appropriate
Model 6517B specifications. For example, assume that the 2 G
Ω
range is being tested, and the
specifications are:
Model 6517B 2 G
Ω
range accuracy: ±(0.225 % of r 1 count)
1 G
Ω
resistor actual value: 1.025 G
Ω
Calculated reading limits are as follows:
Reading limits = 1.025 G
Ω
±[(1.025 G
Ω
0.225 %) + 10 k
Ω
]
Reading limits = 1.025 G
Ω
± 2.31625 M
Ω
Reading limits = 1.02268 G
Ω
to 1.02732 G
Ω
Before performing the ohms verification procedures, calculate the reading limits for each range, and
enter the limits where indicated in the Limits for ohms verification table.
Instrument setup
Before performing the ohms verification procedures, you must make certain that the instrument is
properly configured as follows. Failure to do so results in erroneous or erratic measurements.
Step 1: Select the auto voltage source mode
1. Press
CONFIG
and then
R
.
2. Select
VSOURCE
in the displayed menu, and then press
ENTER
.
3. Select
AUTO
in the VSOURCE SETTING menu, and then press
ENTER
.
4. Press
EXIT
to return to normal display.
Step 2: Select internal voltage source connections
1. Press
CONFIG
and then
OPER
.
2. Select
METER-CONNECT
in the CONFIGURE V-SOURCE menu, and then press
ENTER
.
3. Select
ON
in the SOURCE-METER CONNECT menu, and then press
ENTER
.
4. Press
EXIT
to return to normal display.
Step 3: Disable voltage source resistive limit
1. Press
CONFIG
and then
OPER
.
2. Select
RESISTIVE-LIMIT
in the displayed menu, and then press
ENTER
.
3. Select
OFF
, and then press
ENTER
.
4. Press
EXIT
to return to normal display.
Step 4: Remove ground link
Remove the shorting link between COMMON and chassis ground on the rear panel. Floating
COMMON eliminates ground loops that might result in noise problems.
