![background image](http://html.mh-extra.com/html/keithley/6430/6430_instruction-manual_661765085.webp)
Basic Source-Measure Operation
Temperature changes across components within the instrument can cause the reference and
zero values for the A/D converter to drift due to thermo-electric effects. Auto zero acts to negate
the effects of drift in order to maintain measurement accuracy over time. Without auto zero
enabled, measurements can drift and become erroneous.
Front panel auto zero
Set the auto zero from the front panel as follows:
1.
Press the MENU key.
2.
Select A/D CTRL from the main menu, then press ENTER.
3.
Select AUTO ZERO, then press ENTER.
4.
Select ENABLE or DISABLE as appropriate, then press ENTER.
5.
Press EXIT as necessary to return to normal display.
Remote command auto zero
Use the :SYSTem:AZERo command to enable or disable auto zero via remote. For example,
send the following command to disable auto zero:
:SYST:AZER ON
Conversely, send this command to disable auto-zero:
:SYST:AZER OFF
NPLC caching
NPLC caching speeds up source memory sweeps by caching A/D reference and zero values.
When NPLC caching is enabled (using the NPLC-CACHE/ENABLE menu selection), the A/D
reference and zero values will be saved for up to the 10 most recent voltage, current, and resis-
tance measurement function settings. Whenever the integration rate is changed via the SPEED
key, a recalled user setup (using the SAVESETUP/RESTORE menu selection), or during a
source memory recall (either with the SOURCE-MEMORY/RESTORE menu or during a
source memory sweep), NPLC caching will occur. If the integration rate is already stored in the
cache, the stored reference and zero values are recalled and used. Otherwise, a reference and
zero value are acquired and stored in the cache. If there are already 10 NPLC values stored, the
oldest one will be overwritten by the newest one.
N
OT
E
Auto zero should be disabled for maximum source memory sweep speed; otherwise
the cache is of little use. With auto zero enabled, new A/D reference and zero values
are taken for every reading and saved into the cache, slowing down sweep operation.
However, with auto zero disabled, measurements may drift and become erroneous.
To minimize drift when using NPLC caching with auto zero disabled, periodically
select AUTO-ZERO/ONCE in the A/D-CTRL menu to force an immediate auto zero
update.
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: ......