4-2
Range, Units, Digits, Rate, and Filters
Model 6485 Picoammeter Instruction Manual
Range, units, and digits
Range
The ranges for current measurements are listed in
.
The full scale readings for every measurement range are 5% over range. For example, on
the 20
µ
A range, the maximum input current is ± 21
µ
A. Input values that exceed the maxi-
mum readings cause the overflow message OVRFLOW to be displayed.
Manual ranging
To select a range, press the RANGE
or
key. The instrument changes one range per
key-press. If the instrument displays the OVRFLOW message on a particular range, select
a higher range until an on-range reading is displayed. Use the lowest range possible with-
out causing an overflow to ensure best accuracy and resolution.
Autoranging
When using autorange, the instrument automatically goes to the most sensitive available
range to measure the applied signal. Up-ranging occurs at 105% of range, while
down-ranging occurs at the range value. For example, if on the 20
µ
A range, the instrument
will go up to the 200
µ
A range when the input signal exceeds 21
µ
A. While on the 200
µ
A
range, the instrument will go down to the 20
µ
A range when the input level goes below
20
µ
A.
The AUTO key toggles the instrument between manual ranging and autoranging. The
AUTO annunciator turns on when autoranging is selected. To disable autoranging, press
AUTO or the RANGE
or
key. Pressing AUTO to disable autoranging leaves the
instrument on the present range.
Every time an autorange occurs, a search for every available range of the selected function
is performed. The time it takes to perform the search could slow down range change speed
significantly. Setting upper and/or lower autorange limits can reduce search time.
NOTE
Range limits and groups are not in effect for manual ranging. Every range is
accessible with manual range selection.
Table 4-1
Measurement ranges
nA
µ
A
mA
2nA
2
µ
A
2mA
20nA
20
µ
A
20mA
200nA
200
µ
A
Содержание 6485
Страница 1: ...Model 6485Picoammeter Instruction Manual A G R E A T E R M E A S U R E O F C O N F I D E N C E ...
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Страница 44: ...1 20 Getting Started Model 6485 Picoammeter Instruction Manual ...
Страница 66: ...3 6 Measurements Model 6485 Picoammeter Instruction Manual ...
Страница 138: ...9 20 Remote Operation Model 6485 Picoammeter Instruction Manual ...
Страница 159: ...11 CommonCommands ...
Страница 164: ...11 6 Common Commands Model 6485 Picoammeter Instruction Manual ...
Страница 165: ...12 SCPISignalOriented MeasurementCommands ...
Страница 190: ...14 12 SCPI Reference Tables Model 6485 Picoammeter Instruction Manual ...
Страница 214: ...16 14 Calibration Model 6485 Instruction Manual ...
Страница 219: ...A Specifications ...
Страница 221: ...B StatusandErrorMessages ...
Страница 227: ...C GeneralMeasurement Considerations ...
Страница 233: ...D DDCEmulationCommands ...
Страница 247: ...E ExamplePrograms ...
Страница 250: ...E 4 Example Programs Model 6485 Picoammeter Instruction Manual ...
Страница 251: ...F IEEE 488BusOverview ...
Страница 266: ...F 16 IEEE 488 Bus Overview Model 6485 Picoammeter Instruction Manual ...
Страница 267: ...G IEEE 488andSCPI ConformanceInformation ...
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