RIGOL DP832 accuracy question - Page 1
Forum section: electronics / beginners

author: taran2ula
author_rank: Contributor
timestamp: July 17, 2023, 08:33:35 pm
content: Hello friends and good day to you all. I have a RIGOL DP832 DC power supply with all the upgrades installed. I am musing brand new Pomona banana plug leads. When I set output from RIGOL to 1v exactly and connect the output leads for channel 1 to my FLUKE 87III meter, which has been calibrated, and also another meter Bryman 786, for DC voltage, I get a reading of 1.004v. Is that acceptable to be 4mv off? Please forgive me if my questions sound elementary and stupid to you guys as I am just in the preliminary learning stages and have so much to learn yet. I do apologize in advance.

author: TimFox
author_rank: Super Contributor
timestamp: July 17, 2023, 08:48:56 pm
content: What does the specification sheet for the unit state?On the 5 V full-scale channel, it reads 0.1% of value + 5 mV, or 6 mV worst case.On the 30 V full-scale channels, 0.05% + 20 mV, or 20.5 mV worst case.Assuming you are using the 5 V range, you are exactly within spec, for the 30 V range you are well within spec.I didn't look up the specs on your two voltmeters.

author: bdunham7
author_rank: Super Contributor
timestamp: July 17, 2023, 08:57:52 pm
content: What you are looking for is the specified uncertainty, also sometimes called tolerance, of your 1.000V output. You'd find that in the specifications of each instrument which are found in their respective manuals. Uncertainty can be a complex concept, but for a simple explanation for now just consider it the amount that an actual value can differ from the displayed value.It's not super clear looking at the Rigol manual, but I used what they call the 'readback' specs, which appears to meant the accuracy of the displayed voltage. From the specs of each instrument, I get an uncertainty for the Rigol of 5.5mV and for the Fluke of 2 counts, or 2mV. So if the Fluke reads 1.004, the real value could be anywhere from 1.002 to 1.006 without the meter being deemed out of spec. Likewise, for the Rigol if the display says 1.000V, the actual output could be from 0.9945 to 1.0055V and that would be acceptable.You've actually presented an interesting case because with the data you have, it is very likely that the Rigol is within spec, but not quite a certainty. Can you see why? Perhaps you can look up the Brymen specs and see if it will resolve the matter.

author: bdunham7
author_rank: Super Contributor
timestamp: July 17, 2023, 09:01:02 pm
content: Quote from: TimFox on July 17, 2023, 08:48:56 pmI found this--do you have something different?https://us.rs-online.com/m/d/4013ab7ae939cc40057e100c56fd8002.pdf

author: TimFox
author_rank: Super Contributor
timestamp: July 17, 2023, 09:16:48 pm
content: I looked at this one (yours came up earlier on the Google search).https://beyondmeasure.rigoltech.com/acton/attachment/1579/f-01c9/1/-/-/-/-/file.pdf

author: taran2ula
author_rank: Contributor
timestamp: July 17, 2023, 11:01:13 pm
content: That is exactly what I have and thank you for posting that. Many thanks.

author: taran2ula
author_rank: Contributor
timestamp: July 17, 2023, 11:19:44 pm
content: Thank you very kindly indeed. I am highly grateful for all this feedback. I will read the manual in depth to try and comprehend everything although being a newbie at this stuff I will have to try extra hard, lol. I bought it as a new open box item, and it did come with the manual but didn't notice it until I went back and looked in the box and it was under the carton. I am trying to learn electronics by watching youtube videos (eevblog) and books that I bought. That's what I bought this power supply for. I have a vintage groove box type synthesizer (Yamaha RS7000) that has 10 out of maybe 35, bad tactile buttons and LED's so I am using that as a project. I'm a bit baffled sometimes by the schematic and the idea of conventional current going opposite of actual current. But I'll get it one way or another, lol. I am quite excited about this forum and I think it is valuable beyond compare due to so many electronics people being here and willing to help other people. It is amazing. Thanks guys & gals, and thank you Dave. Have a wonderful evening people.