[SENSe:]FRESistance:APERture
Syntax
[SENSe:]FRESistance:APERture {<seconds>|MIN|MAX|DEF} [, (@<ch_list>)]
[SENSe:]FRESistance:APERture? [{(@<ch_list>)|MIN|MAX}]
Description
This command enables the aperture mode and sets the integration time in seconds (called aperture time) for 4-wire resistance measurements on the specified channels. If you omit the optional <ch_list> parameter, this command applies to the internal DMM, independent of any channels or a scan list.
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You should use this command only when you want precise control of the integration time of the internal DMM. Otherwise, specifying integration time using NPLC (see [SENSe:]FRESistance:NPLC command) executes faster and offers better noise rejection characteristics for values of NPLC greater than 1. |
Used With:
34921A Armature Multiplexer
34922A Armature Multiplexer
34923A Reed Multiplexer (differential mode only)
34924A Reed Multiplexer
34925A FET Multiplexer (differential mode only)
Parameters
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Name |
Type |
Range of Values |
Default Value |
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<seconds> |
Numeric |
Desired aperture time in seconds between 300 µs and 1 second, with 4 µs resolution. MIN = 300 µs, MAX = 1 second |
Aperture disabled. |
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<ch_list> |
Numeric |
One or more channels in the form (@sccc). |
If <ch_list> is omitted, this command applies to the internal DMM. |
Remarks
For the <seconds> parameter, you can substitute MIN or MAX for a numeric value. MIN selects the smallest value accepted, which gives the lowest resolution; MAX selects the largest value accepted, which gives the highest resolution.
If you omit the optional <ch_list> parameter, the configuration applies to the internal DMM, independent of any channels or a scan list (any existing scan list is not redefined). An error is generated if the internal DMM is not installed or is disabled.
Since 2-wire and 4-wire resistance are related functions, changing a measurement parameter for one function will also change the corresponding parameter for the other function (see [SENSe:]RESistance:APERture command).
For 4-wire resistance measurements, the instrument automatically pairs channel n in Bank 1 with channel n+20 in Bank 2 (34921A, 34923A, 34925A) or n+35 (34922A, 34924A) to provide the source and sense connections. For example, make the source connections to the HI and LO terminals on channel 2 in Bank 1 and the sense connections to the HI and LO terminals on channel 22 (or 37) in Bank 2. Specify the paired channel in Bank 1 (source) as the <ch_list> channel (channels in Bank 2 are not allowed in the <ch_list>).
Four-wire measurements are not allowed on the multiplexer modules configured for the single-ended mode (see SYSTem:MODule:WIRE:MODE command).
Only the integral number of power line cycles (1, 2, 10, 20, 100, or 200 PLCs) provide normal mode (line frequency noise) rejection.
The CONFigure, MEASure?, [SENSe:]FRESistance:NPLC, and [SENSe:]FRESistance:RESolution commands disable the aperture time mode (these commands select an integration time in number of power line cycles). You can use the [SENSe:]FRESistance:APERture:ENABled? command to query whether the aperture mode is currently enabled or disabled.
The aperture mode is disabled after a Factory Reset (*RST command). An Instrument Preset (SYSTem:PRESet command) or Card Reset (SYSTem:CPON command) does not change the setting.
Return Format
The query command returns the aperture time in the form "+1.00000000E-01" for each channel specified. Multiple responses are separated by commas. Note that if the aperture mode is currently disabled (see [SENSe:]FRESistance:APERture:ENABled? command), the value returned will represent the previous value specified, not the actual integration time.
Examples
The following command enables the aperture mode and sets the aperture time to 300 ms on channels 3 and 13 in slot 1. For this 4-wire measurement, the instrument automatically pairs these channels in Bank 1 with the corresponding channels in Bank 2.
FRES:APER 300E-03,(@1003,1013)
The following query returns the aperture time selected on channels 3 and 13 in slot 1.
FRES:APER? (@1003,1013) FRES:APER:ENAB? !Verify that aperture mode is enabled ("1")
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Typical Response: |
+3.00000000E-01,+3.00000000E-01 |