New toys and a couple of questions about offsets (Rigol DP832 & DS4014) - Page 1
Forum section: electronics / testgear

author: iggarpe
author_rank: Contributor
timestamp: December 12, 2013, 05:36:03 pm
content: Hi all,I've just found the time to start playing with my new two pieces of equipment from Rigol that arrived a couple of weeks ago: a DP832 power supply with the precision option and a DS4014. I already have a couple of questions. I'm no newbie to this kind of lab equipment though I'm coming from rather old and limited devices.Firstly, the DP832 power supply. See attached picture. All outputs are unloaded and outputs 1 and 2 are displaying a small offset in the current reading. Now, I know this is within specs (as the dealer I bought it from has kindly checked with Rigol, he provides superb customer support), but strikes me as a bit odd that a calibrated instrument displays an offset at the zero reading point. IIRC back in the day when I had to calibrate stuff first thing I did was calibrating out the offset at the zero point. Anyway, just asking other owners: do you see a similar offset in your DP832?.Secondly, I'm also seeing a significant offset at the highest sensibility range in the DS4014 right after switch-on (see 1st picture). As expected the offset lowers as the system warms up (see 2nd picture), though CH4 remains with an offset clearly higher than the rest of the channels. Again I'm almost certain this is all within specs and thus ok, but nonetheless I would like to hear about the experience of other owners.Thanks.

author: iDevice
author_rank: Regular Contributor
timestamp: December 12, 2013, 10:27:44 pm
content: I don't know about the 832 but I have a 1308 and there is no offset.Same for the DS-4014, I have a 4024 and although I could see a slight offset on CH3 after a year, a calibration took mostly took care of it.I say mostly because there is a subtle offset remaining after cal but only a few tenth of micro-volts.So at least for the scope, I would suggest a calibration, the calibration kit comes relatively cheap.But for the PSU, I don't know, although I do remember having read about a bug in the the current reading with the first software that has been fixed with the latest release.

author: thmjpr
author_rank: Regular Contributor
timestamp: December 14, 2013, 05:59:51 am
content: DP832A, similar offsets:CH1: 32V, 0.001A, 0.029WCH2: 32V, 0.001A, 0.016WCH3: 5V, 0.000A, 0.001WIf you go into the manual cal menu in Utility, password is "2012". There are four cal types (V ADC, I ADC, V DAC, I DAC).The odd thing is for I ADC, the 5V channel has a cal point at 0mA. Whereas the 32V channels have first cal point at 10mA.When I selected 10mA it was close enough (~9.56mA), and it only allows 1mA resolution of entry for whatever reason. So I guess you could re-cal it to 1mA lower on the 10mA range, but I haven't tried this, and it would be slightly less accurate.IMO its a bit of a failure of whoever set up these cal points. Realistically though, its within spec so they may not care.

author: iggarpe
author_rank: Contributor
timestamp: December 16, 2013, 07:45:00 am
content: I had already noticed the manual calibration menu but didn't know the password. Don't know to mess much with it unless I do know what I'm doing, Is the manual calibration procedure of the DP832 documented somewhere?.

author: iggarpe
author_rank: Contributor
timestamp: December 16, 2013, 07:48:24 am
content: Quote from: iDevice on December 12, 2013, 10:27:44 pmI'll definitely request a quote for the calibration kit. Haven't seen it priced anywhere.As for the calibration, I noticed that the self-calibration procedure tells you to connect the aux output to all the channels and the external trigger input. The manual doesn't say much more than that too. Has anyone tried this procedure?.

author: clivew
author_rank: Contributor
timestamp: December 16, 2013, 10:06:43 pm
content: Quote from: iggarpe on December 16, 2013, 07:45:00 amI wish