I've a problem with my PXI-4070 I recently purchased.
Input Signal: 4.024 Vdc + 0.101 Vacrms
4070 Configuration:
- NI-DMM Driver: 2.0.1
- Range: 5 V
- Resolution: 6.5 digits
If I use my 4070 configured to "DC Volts" it correctly reads 4.024 V.
If I use my 4070 configured to "AC Volts" it correctly reads 0.101 V.
If I use my 4070 configured to "AC Volts DC coupled " it incorrectly reads 0.098 V.
But if I remove the DC component from the input signal and
use my 4070 configured to "AC Volts DC coupled " it correctly reads 0.101V (still using 5V range).
Although 3 millivolts incorrectness seems not so much but it's much too much for a 6.5 digit DMM. Even worse the error increases as the DC component i
ncreases relative to the AC component.
I hope I'm doing something wrong, but I used my own program as well as the shipped examples and none is working. Maybe you can supply a working example which you tested with a setup as I described above.
Thank You!
BTW I tried this with two PXI-4070 devices (SN: D402F2 & D4254A) and both show the same sympthom.
Kind Regards
Herbert
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Herbert Koltschik
Sagem Communication Austria
herbert.koltschik@sagem.com
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