Author Topic: DP832A output  (Read 6752 times)

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Offline RoGeorge

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Re: DP832A output
« Reply #50 on: January 18, 2019, 09:05:10 pm »
That grounding problem is strange.  My hope is that the DP832 is OK, but some other power supply from other equipment is faulty.

Let's do one last test:
- disconnect all wires (USB, LAN, I/O, all), except the mains power cord
- connect only the halogen bulb at CH1 of the DP832.  No oscilloscope, no other instruments, just the two banana plugs and the bulb (one banana at +, one banana at -)
- no other wires or external jumpers

Does this minimal setup still flashes the bulb?

I am very curious about this ^.  Can you check if the bulb still flashes when there are no extra electrical connections, only the power cord and the halogen bulb, please?

No need to waste extra time for visual evidence, a simple "yes, still flashes" answer will be more than enough.

Offline bson

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Re: DP832A output
« Reply #51 on: January 19, 2019, 03:02:05 am »
I've had it for 3 or 4 years now.  It's pretty big and noisy for its power; the Keithley 2231A-30-3 with similar specs, for example, is the size of a bench DMM.  It had a whole slew of firmware bugs when new, which are fixed now.  It's very easy to calibrate yourself when needed with just a basic multimeter, mine needed updated calibration data when new, but has retained 1mA/1mA readout accuracy since with that initial calibration.  Not sure what they do in the factory, but it was pretty poor.  Those scripts we wrote are still around and get it calibrated.  The 5V output is slightly more accurate that the higher voltage ones.  CV/CC works like they should, OVP and OCP can be disabled if a nuisance with some particular load.

The display is nice, the silly keypad is well, silly, but at least it's a keypad.

I think it's fine budget bench tool, apart from the bulk.  It does the job.  I wouldn't trust it unattended 24x7 though, for any production use.

It can measure rms and averages fine, but has zero ability to analyze or track power transients.
« Last Edit: January 19, 2019, 03:04:03 am by bson »
 

Online blueskull

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Re: DP832A output
« Reply #52 on: January 19, 2019, 03:12:39 am »
the Keithley 2231A-30-3 with similar specs, for example, is the size of a bench DMM.

That thing is heavy as F. I use a 2230G-30-3 at work, and I had a great deal of reluctance moving it around.

Also, it seems like VFD is a great source of noise.

My DMM4050 (Fluke 8846A rebrand) spits a lot of crap to nearby circuit.

Attached scope shot was measured inside an ESD bag as background noise reference, and the same antenna close to the VFD of my DMM4050.

Antanna used was ground clip of Keysight N2894A passive probe, 20MHz BW limit, MSOX6004A, AC coupled, Hi-Res mode.
 

Offline nctnico

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Re: DP832A output
« Reply #53 on: January 19, 2019, 11:46:26 am »
I've had it for 3 or 4 years now.  It's pretty big and noisy for its power; the Keithley 2231A-30-3 with similar specs, for example, is the size of a bench DMM.
Isn't that some kind of rebadge? BK Precision has a very similar looking PSU. Still the Keithley is pretty cheap.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline Jeroen3

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Re: DP832A output
« Reply #54 on: January 19, 2019, 02:29:43 pm »
That grounding problem is strange.  My hope is that the DP832 is OK, but some other power supply from other equipment is faulty.

Let's do one last test:
- disconnect all wires (USB, LAN, I/O, all), except the mains power cord
- connect only the halogen bulb at CH1 of the DP832.  No oscilloscope, no other instruments, just the two banana plugs and the bulb (one banana at +, one banana at -)
- no other wires or external jumpers

Does this minimal setup still flashes the bulb?

I am very curious about this ^.  Can you check if the bulb still flashes when there are no extra electrical connections, only the power cord and the halogen bulb, please?

No need to waste extra time for visual evidence, a simple "yes, still flashes" answer will be more than enough.
Yes. Without any ground (just phase and neutral) it still does. Short circuit current of 2.5A for 280 ms. Or similar in a 10 Ohm of previous post.
With or without ground does not matter much. The supply leaks 0.2 mA.

I was looking to see if I can perform a soft reboot. But scpi does not seem to offer this.
 

Offline bson

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Re: DP832A output
« Reply #55 on: January 20, 2019, 07:37:40 am »
Also, it seems like VFD is a great source of noise.
Doesn't surprise me... (I meant audible fan noise.)

It's possible the Rigol has slightly better specs and precision, though the Keithley is fully floating on all outputs - but the K sure wins on size and (fan) noise!  This might matter if bench space is at a premium (like it is for me), and if you already have a precision supply or just don't need one.
 

Online blueskull

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Re: DP832A output
« Reply #56 on: January 20, 2019, 07:45:15 am »
Also, it seems like VFD is a great source of noise.
Doesn't surprise me... (I meant audible fan noise.)

It's possible the Rigol has slightly better specs and precision, though the Keithley is fully floating on all outputs - but the K sure wins on size and (fan) noise!  This might matter if bench space is at a premium (like it is for me), and if you already have a precision supply or just don't need one.

I ended up demoed an E36313A. Despite the higher rated noise (1mV rms) than its little brothers (350uV rms), measurements show the actual noise is way lower than 350uV even.
So, the next thing the next Tuesday is to order one. Also I will add a 34461A to replace that noisy EMI generator from Tek/Fluke.
 

Offline s8548a

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Re: DP832A output
« Reply #57 on: January 21, 2019, 12:15:12 pm »

Despite the higher rated noise (1mV rms) than its little brothers (350uV rms), measurements show the actual noise is way lower than 350uV even.


sorry for an off topic noob question.

What kind of applications needs like these low psu noise? is there any specification/document available regarding different PARD requirements for different applications?
 

Offline nctnico

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Re: DP832A output
« Reply #58 on: January 21, 2019, 12:55:03 pm »
A low PSU noise helps when working on analog circuits. Chances are you are looking at the signals from the circuit and not the noise which the PSU pushes into your oscilloscope.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 
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Offline Wolfgang

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Re: DP832A output
« Reply #59 on: January 21, 2019, 02:06:32 pm »

Despite the higher rated noise (1mV rms) than its little brothers (350uV rms), measurements show the actual noise is way lower than 350uV even.


sorry for an off topic noob question.

What kind of applications needs like these low psu noise? is there any specification/document available regarding different PARD requirements for different applications?

A field that nees VERY low PSU noise are precision oscillators. All the PSU noise and ripple can show up as unwanted phase noise or sidebands in the oscillator output.
 
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Offline stroh90

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Re: DP832A output
« Reply #60 on: January 21, 2019, 02:20:30 pm »
I have a DP832, bought it 4 years ago.

It also has horrible output spikes on powerup. Batronix and Rigol claimed it was normal. I haven't bought anything from Batronix or Rigol since.

Why people still consider this piece of junk is a mystery to me. It has many documented problems.

However, if you want an expensive, noisy battery charger, it works well enough.
 

Offline glarsson

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Re: DP832A output
« Reply #61 on: January 21, 2019, 02:31:06 pm »
Why blame Batronix? They were correct that this flaw is normal for this PSU.
 

Offline stroh90

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Re: DP832A output
« Reply #62 on: January 21, 2019, 03:58:41 pm »
Ermmm…

Are you saying that retailers have no responsibility for the products they supply??

 

Offline glarsson

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Re: DP832A output
« Reply #63 on: January 21, 2019, 04:05:02 pm »
It depends on what you asked them. If you asked them if this was normal you received the correct answer. If you asked for a refund or similar then you might have reason to complain depending on the circumstances.
 

Offline nctnico

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Re: DP832A output
« Reply #64 on: January 21, 2019, 04:28:39 pm »
It depends on what you asked them. If you asked them if this was normal you received the correct answer. If you asked for a refund or similar then you might have reason to complain depending on the circumstances.
Some suppliers are very quick to say a problem is normal behaviour. Overshoot on a power supply when it is turned on is never normal behaviour -period- so in this case the answer from Batronix was misleading.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline MrFox

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Re: DP832A output
« Reply #65 on: January 21, 2019, 05:44:42 pm »
I got a dp832 a few months ago, despite knowing before hand about the limitations at cold-boot from the mechanical switch. It's a compromise to be aware of, I guess. Same for the big output capacitance, which needs to be taken into consideration when using it for CC.

I haven't found any other PSU with the capabilities I needed unless I pay two or three times the price. And for me in canada the rigol distributors (electro-meters) are the most amazing people I ever had to deal with for support and claims.

I would have prefered the keysight, but it's $2000 CAD versus $600 for the rigol.
 

Offline netdudeuk

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Re: DP832A output
« Reply #66 on: January 21, 2019, 07:08:30 pm »
I have a dp832 hacked to A, ch3 goes to 5.3V, overall very sturdy, but be prepared to change the fan, it's noisy.

DP832 to DP832A ?
 

Offline Gandalf_Sr

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Re: DP832A output
« Reply #67 on: January 22, 2019, 05:33:38 pm »
I have a dp832 hacked to A, ch3 goes to 5.3V, overall very sturdy, but be prepared to change the fan, it's noisy.

DP832 to DP832A ?
I think he means that everything but the (weird) display format is as per the A.  Google 'riglol' and see that there's a site that can give you the keys needed to turn on all A-style features but the display stays the same as the non-A version.
If at first you don't succeed, get a bigger hammer
 

Offline ledtester

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Re: DP832A output
« Reply #68 on: January 22, 2019, 06:33:46 pm »
Here's another opinion for your consideration...


 


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