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Ohms Measurements
4-3
Ohms measurement methods
There are two methods to measure ohms: auto ohms and manual ohms. When using auto
ohms, the SourceMeter operates as a conventional constant current source ohmmeter. To use
this method, simply select an ohms measurement range (or use autorange), and take the reading
from the display. When using auto ohms, the default test current varies with the ohms range, as
summarized in Table 4-1.
NOTE
You cannot change the test current in the auto ohms mode. If you attempt to change
the source current in auto ohms, the SourceMeter will display an error message.
With the manual ohms mode you can select either source V or source I to make ohms mea-
surements, and the unit will automatically compute the resistance reading using the V/I mea-
surement method. After configuring the desired source and selecting a voltage or current
measuring range, select the
Ω
measurement method to display the calculated V/I ohms reading.
NOTE
To achieve optimum accuracy, the SourceMeter measures both V and I and uses
these values in ohms calculations (with source readback enabled). The measured
source value is more accurate than the programmed source value. For remote opera-
tion, the user specifies the functions to measure. See the resistance measurement
accuracy specifications in Appendix A for more information.
Table 4-1
Auto ohms default test currents
Auto ohms range*
Default test current
0
20
Ω
200
Ω
00
2k
Ω
0
20k
Ω
200k
Ω
00
2M
Ω
0
20M
Ω
200M
Ω
00
2G
Ω
0
20G
Ω
200G
Ω
00
2T
Ω
0
20T
Ω
100mA
0
10mA
00
1mA
100mA
0
10mA
00
1mA
00
1mA
100nA
0
10nA
00
1nA
100pA
0
10pA
00
1pA
*200M
Ω
maximum without PreAmp
Summary of Contents for 6430
Page 26: ......
Page 32: ......
Page 78: ...2 14 Connections ...
Page 98: ...3 20 Basic Source Measure Operation ...
Page 138: ...5 30 Source Measure Concepts ...
Page 156: ...6 18 Range Digits Speed and Filters ...
Page 168: ...7 12 Relative and Math ...
Page 176: ...8 8 Data Store ...
Page 202: ...9 26 Sweep Operation ...
Page 248: ...11 22 Limit Testing ...
Page 310: ...16 6 SCPI Signal Oriented Measurement Commands ...
Page 418: ...17 108 SCPI Command Reference ...
Page 450: ...18 32 Performance Verification ...
Page 477: ...A Specifications ...
Page 489: ...B StatusandErrorMessages ...
Page 498: ...B 10 Status and Error Messages ...
Page 499: ...C DataFlow ...
Page 503: ...D IEEE 488BusOverview ...
Page 518: ...D 16 IEEE 488 Bus Overview ...
Page 519: ...E IEEE 488andSCPI ConformanceInformation ...
Page 523: ...F MeasurementConsiderations ...
Page 539: ...G GPIB488 1Protocol ...
Page 557: ......