4071 autorange

[nitad54448]

hi again,

i have another question regarding the 4071 dmm and autorange. When using the express DMM/Switch it is not possible to select autorange and 7.5 digits ? Is there a limitation in this sense ?

thanks again,

Regards

[Brandon_G. · Accepted solution]

Hi Nitad,

By default, auto-ranging is configured for 5 1/2 digit resolution and can not be changed in the Express vi.  However, auto-ranging at 7 1/2 digits can be accomplished by manually configuring the DMM to the 7 1/2 digit settings listed in the DMM Measurement Defaults in the DMM Help.  You will have to use the lower level VIs (instead of the Express VI) to configure your measurements for 7 1/2 digits.  For reference, I've listed the 7 1/2 digit settings you will have to explicitly configure.

Aperture Time:  100 ms

Auto-Zero: On

ADC Cal: On

DC Nose Rejection: High-Order

Number of Averages: 4

You can look in the Example Finder to find an example that would be a good starting point to modify your code to auto-range at 7 1/2 digits.  In the Example Finder folder, I would use the example located at: Hardware Input and Output --> Modular Instruments --> NI-DMM (Digital Multimeters) --> Single Measurements --> Measure Resistance (2 or 4-wire).vi.

When using  7 1/2 digits in auto-range, your total measurement time will be long.  Each range measured is at 7 1/2 digits, so when the DMM has to scan different ranges to find the optimal range, the total time can get long quick.

cheers!

Brandon G