3-6
Range, Digits, Rate, and Filter
Rate
The RATE key selects the integration time of the A/D converter. This is the period of time the
input signal is measured (also known as aperture). The integration time affects the amount of
reading noise, as well as the ultimate reading rate of the instrument. The integration time is
specified in parameters based on a number of power line cycles (NPLC), where 1 PLC for 60Hz
is 16.67msec (1/60) and 1 PLC for 50Hz (and 400Hz) is 20msec (1/50).
In general, the Model 2182 has a parabola-like shape for its speed vs. noise characteristics
and is shown in
. The Model 2182 is optimized for the 1 PLC to 5 PLC reading rate.
At these speeds (Lowest noise region in the graph), the Model 2182 will make corrections for
its own internal drift and still be fast enough to settle a step response <100ms.
Figure 3-1
Speed vs. noise characteristics
You can have a separate rate setting for voltage and temperature functions. The rate setting
for a voltage function applies to the other voltage function. For example, if you set DCV1 for
0.1 PLC (fast), DCV2 will also be set for 0.1 PLC (fast). Similarly, the rate setting for a
temperature function applies to the other temperature function. Setting TEMP1 for 5 PLC
(slow), also sets TEMP2 for 5 PLC (slow).
Front panel RATE selections are explained as follows:
•
0.1 PLC — Selects the fastest front panel integration time. Select 0.1 PLC (fast) if speed
is of primary importance (at the expense of increased reading noise).
•
1 PLC — Selects a medium integration time. Select 1 PLC (medium) when a
compromise between noise performance and speed is acceptable.
•
5 PLC — Selects the slowest front panel integration time. Selecting 5 PLC (slow)
provides better noise performance at the expense of speed.
Lowest
noise
region
Voltage
Noise
166.7
µ
s
16.67ms
83.33ms
Aperture Time
1s
Summary of Contents for 2182
Page 1: ...www tek com keithley Model 2182 2182A Nanovoltmeter User s Manual 2182A 900 01 Rev B May 2017...
Page 18: ......
Page 22: ......
Page 23: ...1 Getting Started Getting Started...
Page 41: ...2 VoltageandTemperature Measurements Voltageand Temperature Measurements...
Page 68: ...2 28 Voltage and Temperature Measurements...
Page 69: ...3 Range Digits Rate andFilter Range Digits Rate andFilter...
Page 82: ...3 14 Range Digits Rate and Filter...
Page 83: ...4 Relative mX b and Percent Relative mX b andPercent...
Page 91: ...5 RatioandDelta Ratioand Delta...
Page 117: ...6 Buffer Buffer...
Page 123: ...7 Triggering Triggering...
Page 140: ...7 18 Triggering...
Page 141: ...8 Limits Limits...
Page 149: ...9 SteppingandScanning Steppingand Scanning...
Page 168: ...9 20 Stepping and Scanning...
Page 169: ...10 AnalogOutput Analog Output...
Page 175: ...11 RemoteOperation Remote Operation...
Page 205: ...12 CommonCommands Common Commands...
Page 221: ...13 SCPISignalOriented Measurement Commands SCPISignalOri entedMeasure ment Commands...
Page 225: ...14 SCPIReferenceTables SCPIRefer enceTables...
Page 239: ...15 AdditionalSCPI Commands Additional SCPICom mands...
Page 260: ...15 22 Additional SCPI Commands...
Page 261: ...A Specifications Specifications...
Page 263: ...B Statusand ErrorMessages StatusandError Messages...
Page 268: ...B 6 Status and Error Messages...
Page 269: ...C Measurement Considerations Measurement Consider ations...
Page 278: ...C 10 Measurement Considerations...
Page 279: ...D Model182Emulation Commands Model182 EmulationCom mands...
Page 284: ...D 6 Model 182 Emulation Commands...
Page 285: ...E Example Programs ExamplePro grams...
Page 293: ...F IEEE 488 BusOverview IEEE 488Bus Overview...
Page 307: ...G IEEE 488andSCPI ConformanceInformation IEEE 488and SCPIConform anceInforma tion...
Page 310: ...G 4 IEEE 488 and SCPI Conformance Information...
Page 311: ...H Measurement Queries Measurement Queries...
Page 316: ...H 6 Measurement Queries...
Page 317: ...I Delta PulseDelta and DifferentialConductance Delta Pulse Deltaand Dif ferentialCon ductance...