if you source current from Ch3+ and sink it into Ch2-, the current flows through the voltage sense wires and induces a drop (and therefore error in voltage readout/regulation)
You wouldnt think remote sense would be needed for a 3A supply. 1 + 1 =2 Feet of AWG18 would be about 40mV. Remote sense can really hamper dynamic response and is more likely to cause stability issues.
The accuracy spec is probably for at the terminals. You can’t really cant really spec accuracy any other way then where it is sensed.
I threatened it in the original video, and it's only been several months, so I figured it was time! I soldered a bit of 3mm (!) copper wire between the two negative terminals, and the problem is fixed, no surprises. Post-fix, voltage sag on channel 2 is about a millivolt or so (noise floor of my cheapo DMM, compare to 57mV dip pre-fix) when injecting 3A up where it doesn't expect it. A video demonstrating the (more-or-less ideal) behaviour of the supply after the fix is below. No, there's no video of the fix itself, sorry! I don't have Dave's talk-and-fix-and-operate-camera-at-same-time skillz...
I intend to buy such a power supply, maybe someone who bought it recently could confirm or not that it is fixed in the mean time?
I intend to buy such a power supply, maybe someone who bought it recently could confirm or not that it is fixed in the mean time?
I intend to buy such a power supply, maybe someone who bought it recently could confirm or not that it is fixed in the mean time?
Hi eurofox, there were some similar questions about the DP832 status, which I replied to here.
Also, you may wish to follow my thread on DP832 firmware bugs and hardware issues here. I will try to keep the thread up-to-date.
As for the specific issue you mention (design fault related to current sense between GND terminals of channels 2 and 3), we don't know whether Rigol will correct it in a future hardware revision, but so far there are no reports of them fixing this issue. If I have to guess, I would say it is not likely they will provide a fix --- they had a chance to do it when the LM317 heatsink problem was addressed, and also Rigol has replied directly about this issue in "DP832 Recommended Connections.pdf" (see my thread linked above, or post #30 above by AndersAnd) in which they suggest installing a heavy duty GND wire yourself.
Hope that helps!
I intend to buy such a power supply, maybe someone who bought it recently could confirm or not that it is fixed in the mean time?
I will be checking mine out when it arrives. But the ship notice for my DSO4054 also includes a ship date of 2014-05-02 for the DP832. Looks like the DM3068 is also 2014-05-02.
Maybe they are reworking the DP832 again. Or TEquipment just has stock issues.
I appreciate the delay is none of TEquipments fault but would like to be reassured that first come first served is somewhat the policy?
we have a few hundred coming in on this shipment with about 100 left so we are good.. ( when they finally get there )
Thanks again for the business.
I just got 5 kids to bed. After 11 hours of work I'm dead tired.
Cheers and many thanks for the business!
Evan Cirelli
TEquipment.NET
(design fault related to current sense between GND terminals of channels 2 and 3), we don't know whether Rigol will correct it in a future hardware revision, but so far there are no reports of them fixing this issue. If I have to guess, I would say it is not likely they will provide a fix --- they had a chance to do it when the LM317 heatsink problem was addressed, and also Rigol has replied directly about this issue in "DP832 Recommended Connections.pdf" (see my thread linked above, or post #30 above by AndersAnd) in which they suggest installing a heavy duty GND wire yourself.
So I found this thread while I'm reading up on this psu, so I guess the situation still is the same on this?
Not sure in what situation I would combine ch2 and ch3, but I would use an combination of ch1 and ch2 to provide -15/+15 power, but I guess I would use ch3 for powering the 5v part of the same circuit, would I be in this situation then?
on the DP831, did they change this there?, the ch1 is the low-voltage channel, and ch2+ch3 is the ones with higher voltage, and common ground it seems from the pictures.
Maybe just continue looking...
So if I understand correctly, if one wants to drive dual rail Op Amps and some digital logic (with split analog/digital grounds), one would be better off with something like the GW Instek GPS-3303S or an QL564T by Aim-TTi, without common grounds, but then one would be looking at two to three times the cost of the rigol?
(Power supplies taken arbitrarily from a Swiss distributor website, I checked for 3 outputs and > 195 W and the price not in the stratospheric range)