Are these readings normal for the rigol dp832a

[cpposteve]

Hi All

hope you can shed some light on this for me.

just received my rigol DP832A (bloody noisy fan)
just checking measurements to see how it performs.
now for example (as the pictures will show) if i set the output to 30.111 volts, the top line shows 30.120 (weird) and the set at the bottom is 30.111 ( to be expected)
on cheking the output with my eevblog meter it is reading the correct voltage withing a few milivolts, yet the voltage displayed at the top is showing 9mv more than it should.
is this normal?

cheers

steve

P.S. is there anyway to turn the fan off while not under load?

[thm_w]

You can check the manual here to see if its within specifications: http://beyondmeasure.rigoltech.com/acton/attachment/1579/f-01c9/1/-/-/-/-/file.pdf
See Readback voltage.
Assuming the 121GW is perfectly calibrated as well.

The fan should turn on high on power up, then ramp down after a few seconds. Some users have replaced with a quieter model.
https://www.eevblog.com/forum/testgear/rigol-dp832-firmware-updates-and-bug-list/
https://www.eevblog.com/forum/testgear/how-noisy-is-a-rigol-dp832/

[NY2KW]

I just checked on my 2+ year old DP832A and I do not find that inconsistency.  Have you checked other settings?

[JDubU]

It may be within specs but it can be re-calibrated for better accuracy. I've re-calibrated mine and now get one millivolt accuracy for almost all of each range.  It cannot be calibrated perfectly because it acts like, internally, the set voltage has a coarser resolution than the read back voltage (difference in D/A vs A/D resolution?).

If you have an appropriate benchtop DMM, you can calibrate it yourself:
https://github.com/stupid-beard/dp832cal
https://www.eevblog.com/forum/testgear/rigol-dp832-firmware-updates-and-bug-list/600/

[cpposteve]

I have since re calibrated this and now all good. Thanks for the reply