EEVBlog #439 - Atten PPS3205T-3S Triple Output Power Supply Review

[Salas]

Its core abilities at the price look quite much and it seems basically delivering them safely. When we approach an $500 outlay for a PSU we need it be a product though, don't we? Can a non supporting brand which not even replies a simple email query and has the basic PC remote control thing non functional as it comes be considered as offering a product at the price or just a "shipment"? If it was to be well functioning with nice PC software, having good support, warranty to be expected honored etc. and would cost how much? $750-1000, which ones are the offerings it should really be compared to? Something from TTI maybe?

[Teemo]

Perfect review! Thanks Dave!

I guess this kind of equipment is the source of inspiration. It just sits on the bench and sometimes you turn it on, and then turn it off again and think:"Why not to design a decent power supply with decent UI"...

[EEVblog]

Its core abilities at the price look quite much and it seems basically delivering them safely. When we approach an $500 outlay for a PSU we need it be a product though, don't we? Can a non supporting brand which not even replies a simple email query and has the basic PC remote control thing non functional as it comes be considered as offering a product at the price or just a "shipment"? If it was to be well functioning with nice PC software, having good support, warranty to be expected honored etc. and would cost how much? $750-1000, which ones are the offerings it should really be compared to? Something from TTI maybe?

Well, that's the question isn't it.
It's a crappy interface PSU very much built down to a price, but it has performance and features unmatched at the price AFAIK. You get to decide what you want, that's what the free market is for. If there is a comparable feature one at a comparable price, then this one is a dead duck. Until then, it has a market.

Dave.

[Galenbo]

With a power supply, however, the designers are the same people as the target market! What is going on?

The people who write Specs in Word documents, the ones who go to meetings to decide how the UI will look, have nothing in common with the ones who are using that kind of equipment.

.

[Galenbo]

So the hardware is ok, but the software is crap?

Run Linux on it :-)

I mean, where is the open source project to reprogram the chip?
Or cut the chip out, replace it with another...

[Rerouter]

out of curiosity did you try and force the over voltage protection past the specifications, or even with the knob + button if it can be tricked into going to a greater voltage,

if so it would be interesting just how far that glitch could be exploited, e.g. finding its maximum possible output, and seeing if it can survive at that,

[amyk]

I had a look inside. The separate serial board goes to an MCU board, centered around a chip labelled STC 89C58RD+. A quick google turned up a datasheet that contains a few package outlines and no text whatsoever. Good luck getting it to work by reverse engineering that.

STC 89C58, standard 8051-based MCU. STC is a Chinese manufacturer.

The pinout is nearly the same as the NXP 89C58, except it looks like STC's version has an extra 4 ports. This appears to be the Chinese datasheet for it.

Edit: AT89C51 also has the same pinout (without the 4 extra ports) so this is probably a pretty standard part.

[amspire]

The OVP feature can actually make it a safer supply than better higher prices supplies that don't have that feature.

Do you know how they have implemented the OVP? The traditional OVP circuits are independent from the rest of the power supply circuitry so they can protect the load from power supply failure. In the case of shorted regulator transistors, the OVP is meant to protect the load by forcing the power supply's fuse to blow. If the OVP level is set by a DAC controlled directly by the main processor, it is not independent.

Do they have a separate controller and separate supply just for the OVP?

[mkwired]

Is that 67 kHz noise coming from the fluorescent lights?

[firewalker]

More likely the PWM for the led panels.

Alexander.

[EEVblog]

Do they have a separate controller and separate supply just for the OVP?

No, it appears not, and I noted how it's usually done in the review.
It appears to be software based, done by the local processor on each output board.
It's better than having no OVP at all. Prevents you from having a brain fart operating the front panel.

Dave.

[Rufus]

The fan which sounds like it has bad bearings could just be low frequency PWM speed control.

[Lightages]

Too bad. I was looking for another power supply but with the shitty controls it is worthless. As others have said the user interface can cause some real problems. Sorry Dave but I am disappointed that you accept this as not a fail.

When did I say it's not a fail? I spent maybe 30min complaining about the bloody thing!
Will I personally continue to use it, well, yes, I've persevere because it's the most versatile supply in my lab. Just like I find my Fluke 87V defaulting to AC current incredibly annoying, but I continue to use it.

Yes you complained and then gave it a thumb sideways. I took that as not a fail overall. I do see your point about the actual output being good but its interface lets it down to the point of total failure, IMHO only.

[staxquad]

Too bad. I was looking for another power supply but with the shitty controls it is worthless. As others have said the user interface can cause some real problems. Sorry Dave but I am disappointed that you accept this as not a fail.

When did I say it's not a fail? I spent maybe 30min complaining about the bloody thing!
Will I personally continue to use it, well, yes, I've persevere because it's the most versatile supply in my lab. Just like I find my Fluke 87V defaulting to AC current incredibly annoying, but I continue to use it.

Yes you complained and then gave it a thumb sideways. I took that as not a fail overall. I do see your point about the actual output being good but its interface lets it down to the point of total failure, IMHO only.

and if a firmware update ever came along to solve those problems? 

[dentaku]

If I had one I would program it to output 16 step looping sequences to control a voltage controlled oscillator (VCO) just like in the old days before MIDI.
It's completely not what it's intended for and would make some of the old time geeks angry because "it's not what it was designed to do"

[rsjsouza]

Dave, I congratulate your patience in plowing through the issues in this video without throwing the whole thing in the trash can. Halfway through the video I was pulling my hair and had to stop and watch the rest of it at a later time...

What the heck do these designers have in mind to not go through a tried and proven panel interface with two rotary encoders (voltage/current)? If this exists for so long it is because there is a good reason for that... 

 

[biot]

This appears to be the Chinese datasheet for it.

Thanks! The URL on that PDF led me to the English version. It has ISP functionality, but it's not immediately obvious to me if there's a way to dump the existing firmware in the MCU's flash out to the computer though. I'll need that if I'm ever going to get a list of serial commands (as Dave was not forthcoming).

[bkubicek]

Open letter to the product mangers of Atten:

Dear decision maker for Atten power supplies!

I really enjoy the price/quality ratio of your products. However, one of the problems of your devices is the firmware. There is room for improvement.
If you had better firmware, you would sell much more devices.
But how can you do this without spending research and development money from your side?

There are many many programmers out there, who are willing to improve your firmware for free. The only prerequisite is that you would publish the firmware as open source, i.g. GPLv3 or later.
By distributing the firmware source code, programmers all over the world would be enabled to create a better, improved firmware, even after your product development phase is finished. Leading to a large community of users. Not to speak of the media hype.

An example for this was the Linksys, who in completely different circumstances published their firmware as open source. Now they sell much more devices, because its an important feature that the firmware is open, improved, and also improvable in the future.

It you would allow this for your power supplies, it could be a unique selling point for your devices, which are perfectly aimed at many many makers/producers out there.

very nice greetings,
 Bernhard Kubicek

[tinhead]

lol, Open Source means "everybody can and will for sure clone my products".

Do you really think a product, build down to the price, programmed by underpaid engineers (or even students)
can be improved with open source?

Not really, there is no room for ANY kind of competitions/lose of money - and open source is competition
and lose of money (where is linksys now? they already gone, and i know ppl who got fired there).
This can only work when you protect your design by custmized hardware, when nobody else can get the specific
chip/asic they you can publish any kind of info and work with open source ppl (but then still someone, if there
is enough profit, will clone your custom chip).

There is even no need for anything else than some simple improvements in code (due the language
differences it is important to make pictures, videos, what so ever, to document exactly what is bad and how can be done better)
, they can be done by their engineers (or even students, heh), all you need to do is to push ATTEN (as i did with Tekway/Hantek).

All they care about is profit, nothing else. Bad reviews on highly known forums, lot of emails - this all are
the things they worry about - to not lose a single cent - but not a open source proposals^^.

[amyk]

This appears to be the Chinese datasheet for it.

Thanks! The URL on that PDF led me to the English version. It has ISP functionality, but it's not immediately obvious to me if there's a way to dump the existing firmware in the MCU's flash out to the computer though. I'll need that if I'm ever going to get a list of serial commands (as Dave was not forthcoming).

Their programming software doesn't appear to have a "verify" function either, so I guess ISP won't do it. But it's a standard-looking package 89c58... perhaps holding it in reset and doing the usual thing on an 8051 parallel programmer would work (if security bits aren't set). At least see if you can read its ID that way. Maybe STC cloned some other manufacturer's 89c5x design and just wrote an ISP bootloader to it.

[firewalker]

Do they offer new firmware capability through the USB port? Using a bootloader etc.

Alexander.

[Rerouter]

dave's one is 1.0, so i would hazard a guess that there isn't any updated for this specific model,

[poodyp]

I thought that wasn't the proper way to get the noise of a power supply, and you had to use a differential probe to get a true reading.

[Oracle]

what a useless firmware.. Horrific!

[Marco]

This can only work when you protect your design by custmized hardware, when nobody else can get the specific
chip/asic they you can publish any kind of info and work with open source ppl (but then still someone, if there
is enough profit, will clone your custom chip).

But cloning the firmware without open source is impossible? What a strange argument, if they want to clone you they will ... period.

Not going open source can not stop it, all you can do to distinguish yourself is to deliver quality consistently ... extendibility is a quality. A better reason against open source is that a lot of hardware in this business is rather artificially restricted to increase margins on higher end hardware.

I am 100% certain that the Linksys wrt54g made back it's non recurring costs back 1000s of times over ... I bet they wish all their devices failed as hard as that, they wouldn't have had to fire your friends then.