Did Rigol fix the DP832's "EEV Blog Fails"? - Page 1
Forum section: electronics / testgear

author: SpannersToSparks
author_rank: Regular Contributor
timestamp: January 25, 2017, 04:47:08 pm
content: HiI am considering picking up the Rigol DP832, but watching Dave's series of videos on it put me off. Unfortunately, there doesn't seem to be much else in the same price bracket (£430 is about my max) of note. I'm not too keen buying second hand or refurbished, and if I can avoid buying off ebay, at least for my main PSU, I would rather do so.Did Rigol fix the issues with the binding posts being on a common ground, and the inaccuracy of reported current? It looks fully featured but if I am spending that much on a piece of kit I hope to last a while, it would be reassuring to know there arent any problems before its even out the box.Cheers

author: Silveruser
author_rank: Regular Contributor
timestamp: January 25, 2017, 06:04:47 pm
content: https://www.eevblog.com/forum/testgear/rigol-dp832-firmware-updates-and-bug-list/msg361709/#msg361709Is the long thread of updates and fixes.The common ground between ch 2 & 3 remains and is explained in a note. It should not be a problem if you are aware of it and connect everything correctly. Unless you need three totally independent channels, then yes it is a problem/

author: rstofer
author_rank: Super Contributor
timestamp: January 25, 2017, 08:35:04 pm
content: Quote from: Silveruser on January 25, 2017, 06:04:47 pmSo, if you want +-15v and +5V, Ch1 MUST be the negative supply (because it doesn't have a common ground), Ch2 MUST be the positive supply and Ch3 will be the +5V supply.Not a big deal. Rigol has an app note on how to properly connect the supplies.For what I do, op amps and logic, the common ground is not an issue. YMMV...

author: 2N3055
author_rank: Super Contributor
timestamp: January 25, 2017, 08:52:09 pm
content: If you need dual +-30V and separate 5V than you have DP831 for that... DP831 has channels connected differently.. +-30V have common ground , 0-8V channel is isolated...That is why I didn't buy DP832 but instead got DP831... No problems with the channels at all..

author: SpannersToSparks
author_rank: Regular Contributor
timestamp: January 25, 2017, 08:56:32 pm
content: OK thanks chaps, looks like the Rigol is back on the table for consideration.

author: SpannersToSparks
author_rank: Regular Contributor
timestamp: January 25, 2017, 09:04:54 pm
content: Quote from: SpannersToSparks on January 25, 2017, 08:56:32 pmYeah I spotted that on the Rigol site. I am still learning, so can you explain why the 831 has a -30 and a +30, and what the difference is to the 832 with 2 x +30?I'm a mechie by trade and we're a bit of a slow breedCheers

author: tggzzz
author_rank: Super Contributor
timestamp: January 25, 2017, 09:06:54 pm
content: Quote from: SpannersToSparks on January 25, 2017, 04:47:08 pmFor a simple non-programmable linear PSU, I pick up old Farnells for £10-£20 at local auctions. I put a 300W resistor across the outputs to test it.The worst I've had to do is change a capacitor and deoxidise some pots. Cost: ~£60.Now, what do I want to buy with the other £350? Of course, you may place a significant value on your time

author: 2N3055
author_rank: Super Contributor
timestamp: January 25, 2017, 09:51:06 pm
content: Quote from: SpannersToSparks on January 25, 2017, 09:04:54 pmNo worry mate, glad to help..When you have 3 channels that are completely isolated, you can connect them in any parallel or serial combination... In reality that is best combination..DP831 has two 30V channels connected in series, with middle connection being ground and separate 8V channel:separate(+)--8V--(-)and(+)--30V--(GND)--30--(-)DP832 has one 30V channel connected with common ground with 5V channel,and separate 30V channel:separate(+)--30V--(-)and(+)--30V--(GND)--5V--(-)If you need more than 30V then you connect two channels in series for 60V... DP831 already has that connected.. But you can't connect two 30V channels in parallel to get 30V and double the current..On DP832 you can connect 30V channels in series and parallel..But on DP832 you can't have +- dual 30V supply AND 5V have common ground... And that is combination I use... I use +-15V for opamps and 3-5V for logic circuits on a same board with common ground... I can also route analog and digital grounds separately and connect them at the board at proper place in circuit..Since that's the kind of stuff I do, I bought DP831... I also have two cheap linear 30V/3A PSU that I can use for crazy combinations... Those together work very well for me.. I also like that "logic supply" channel goes to 8V and 5A... That is good for testing logic supplies to max specs, and also I usually need more current for logic...On bad side, DP831 has only 2A on 30V channels.. But I have other supplies for that if I need...So, like all instruments and tools... Tools for the job... DP831 is perfect for me, DP832 not so much.. But you need to find what you need..Take care !

author: rstofer
author_rank: Super Contributor
timestamp: January 25, 2017, 10:06:48 pm
content: Quote from: 2N3055 on January 25, 2017, 09:51:06 pm

author: 2N3055
author_rank: Super Contributor
timestamp: January 25, 2017, 10:16:14 pm
content: Quote from: rstofer on January 25, 2017, 10:06:48 pmNo, you're right, I didn't see right how 30V channel is connected to 5V channel.. They are not in series but have common (-)..So logically you can connect other 30V channel in negative direction..But DP831 has no current shunt share problem and is already in config I use it most of the time, so I chose DP831....For other combinations I just combine with other PSU-s..Thank you for setting me straight.. I appreciate it!!Take care!

author: SpannersToSparks
author_rank: Regular Contributor
timestamp: February 08, 2017, 06:37:46 pm
content: Hi chapsWhat do you all make of this?https://www.amazon.co.uk/High-Precision-Adjustable-KORAD-Supply-KA3005D/dp/B0084JFWNY/ref=sr_1_fkmr0_1?s=diy&ie=UTF8&qid=1486578714&sr=1-1-fkmr0&keywords=Korad+KA3005PIt was reviewed by EEV blog and after a false start, declared a winner. Do you think I could get away with buying two of these and use them for The Art Of Electronics student course? (Digital and Analog parts). Or maybe buy one at first, then get a second if its really needed? I Also need to pick up a function generator, components, bread boards etc etc etcRandom thought: The problem with buying stuff for a course of learning is that you need to have taken the course of learning to really know what you needed to buy in the first place...

author: rstofer
author_rank: Super Contributor
timestamp: February 08, 2017, 06:50:17 pm
content: Quote from: SpannersToSparks on February 08, 2017, 06:37:46 pmYou can certainly use this single output supply but... One of the things the Rigol 832 has is a common Output ON/OFF button. All 3 supplies are turned on and off together. It seems to me that this is important but maybe not. I would certainly want to shut off the op amps before I shut off the uC or at least turn them off together. I wouldn't want the op amp supplies feeding through the uC ADC and potentially trying to power the uC. That kind of thing...