2-8
Connections
2-wire sensing
When using 2-wire sensing to source and/or measure voltage, the error associated with IR
drops in the test leads could be significant. The ratio between the test lead resistance and DUT
resistance determines the error that is introduced. If the error introduced by the IR drop of the
test leads is not acceptable, use 4-wire sensing.
For example, assume test lead resistance (R
L
) is 1
Ω
and the DUT resistance (R
DUT
) is
10k
Ω
. The error is calculated as follows:
Error = R
L
/ R
DUT
= 1
Ω
/ 10k
Ω
= 0.0001
= 0.01%
Notice that as the resistance of the DUT increases, the error decreases. For DUT above
1G
Ω
, guarding should also be used. See
Cable guard
.
Since current in a series circuit is the same at all points in the loop, remote sensing does not
improve I-Source or I-Measure accuracy. Thus, if sourcing current and measuring current, you
can use local sensing.
NOTE
For Measure Only (V or I) operation, 2-wire sensing must be used.
4-wire sensing
Voltage source and measure accuracy are optimized by using 4-wire sense connections.
When sourcing voltage, 4-wire sensing ensures that the programmed voltage is delivered to the
DUT. When measuring voltage, only the voltage drop across the DUT is measured.
Use 4-wire sensing for the following source-measure conditions:
•
The error contributed by test lead resistance for local sensing is not acceptable.
•
Optimum Ohms, V-Source, and/or V-Measure accuracy are required.
4-wire sensing specification clarifications
•
There is no hardware configurations needed to enable 4-wire sense. Simply hook up the
sense wires; otherwise, the Model 6430 will sense the voltage locally through resistors.
•
Specified accuracies for both source and measure are only achieved using 4-wire
sensing.
•
Sense wires must be no more than 10
Ω
per lead.
Содержание 6430
Страница 26: ......
Страница 32: ......
Страница 78: ...2 14 Connections ...
Страница 98: ...3 20 Basic Source Measure Operation ...
Страница 138: ...5 30 Source Measure Concepts ...
Страница 156: ...6 18 Range Digits Speed and Filters ...
Страница 168: ...7 12 Relative and Math ...
Страница 176: ...8 8 Data Store ...
Страница 202: ...9 26 Sweep Operation ...
Страница 248: ...11 22 Limit Testing ...
Страница 310: ...16 6 SCPI Signal Oriented Measurement Commands ...
Страница 418: ...17 108 SCPI Command Reference ...
Страница 450: ...18 32 Performance Verification ...
Страница 477: ...A Specifications ...
Страница 489: ...B StatusandErrorMessages ...
Страница 498: ...B 10 Status and Error Messages ...
Страница 499: ...C DataFlow ...
Страница 503: ...D IEEE 488BusOverview ...
Страница 518: ...D 16 IEEE 488 Bus Overview ...
Страница 519: ...E IEEE 488andSCPI ConformanceInformation ...
Страница 523: ...F MeasurementConsiderations ...
Страница 539: ...G GPIB488 1Protocol ...
Страница 557: ......