UNI-T UDB3000S Series: UDP3305S / UDP3305S-E

[thephil]

Good point. Missing VAT would explain the difference in price. I don't speak Croatian so I don't know...

[2N3055]

@audiotubes: Seems like it's cheaper in croatia: https://www.chipoteka.hr/alati/izvori-i-napajanja/laboratorijski-izvor-2x32v-2x5a-5v-udp3305s-uni-trend-9150044680.

Disclaimer: I have never bought from that shop so I wouldn't know if it's real or a scam...

That price should include 25% VAT. Chipoteka is a old (since 1990) electronics vendor and very serious and trustworthy company.
Chipoteka seems to have very good deal with UNI-T and UNI-T prices are very good, have been since forever.

[thephil]

Okay, now i see, S version have on all channel ADC 16bit (ADS1118IDGSR) and 16bit DAC (DAC8562), S-E version have ADC 16bit (ADS1118IDGSR) and 14bit DAC (DAC8162).

Oh – now the numbers you measured make perfect sense:

32 V / 2¹⁶ = 0.0004882812 V

32 V / 2¹⁴ =  0.001953125 V

So ≈ 2mV is the resolution of the 14bit DAC. May still be worth the software upgrade for some – even without replacing the DACs. But, of course, I'm curious to see if you can fully convert it and figure out the calibration. Keeping my fingers crossed.

[faktorqm]

Hello there, just about to buy one of this power supplies from UNI-T. The quality/price is awesome, vs Siglent/Rigol brands. We will wait for the iAleks mods to check if the mod works. Thank you! Regards!

[faktorqm]

Okay, now i see, S version have on all channel ADC 16bit (ADS1118IDGSR) and 16bit DAC (DAC8562), S-E version have ADC 16bit (ADS1118IDGSR) and 14bit DAC (DAC8162).
Il try order DAC8562, after place new ic it need calibration.. but im try it.

Hey iAleks! one question: could you please repeat the test made by thephil regarding channel power raising? I'm a little worried about those oscilloscope shots. I'm talking about the section "On/Off behaviour" on his blog https://techbotch.org/blog/lab-power-supply/index_en.html I think could be a good test to see if your units behaves same way.

@thephil: Thanks a lot for your review! I'm worried about the channel rising waveform, could be an escenario where this has to be a problem? I'm also looking for the owon ODP6033 and there is a review on youtube and this problem is not present, however it's a 3A power supply so I don't like it very much.

Thank you for your time guys!

[thephil]

Can the on-behaviour be a problem? I don't know.

Personally, I'm not too worried about it and have had no problems with it. But maybe someone with more knowledge could comment on this. Maybe it could confuse a sensitive circuit if the voltage struggles a bit before settling at the set value?

[RiRaRi]

Just one off topic question: if you lets say service a device for 2 hours and you use PSU for 5 minutes, then 20 nothing, then again for 5 minutes etc. Is it better to turn it off completly and then power it on after 20/30 minutes or just leave it on for 2 hours straight even if it not in use and just turn off channels?

BTW I am very happy with UNI-T model, feels very solid and everything is great for now. Highly reccomend but it is only in use for few days.

[faktorqm]

Thanks for your feedback. I want to wait if there are any black friday discount or something like that.

Answering your question, I would let the power supply ON and the reason is temperature. All the components are under working conditions and has been stabilized their own temperature drifts.

I hope iAleks will answer this thread!

[RiRaRi]

Okay. Like someone said before: in Chipoteka web shop from Croatia this E model cost 390 EUR which is very good price

[Doman]

I own a UDP3305S, and I'm having difficulty understanding how the Over Current Protection (OCP) function operates on this device. My unit is running software version 1.10 and bootloader 1.04.

The Power Supply does not allow setting the OCP lower than the Current; it can only be set higher or equal. On channel 1, when I set it to 1A, it shifts into Constant Current (CC) mode when I draw more than 1A but does not activate the OCP. However, the OCP is triggered when I set it to 0.999A or 0.993A. This is likely a rounding error. And it never ever wants to switch channel off when OCP is set higher than current.

I can't understand why it doesn’t allow the OCP value to be set lower than the current? Am I misunderstanding how OCP should work?

Hey iAleks! one question: could you please repeat the test made by thephil regarding channel power raising? I'm a little worried about those oscilloscope shots. I'm talking about the section "On/Off behaviour" on his blog [...]
@thephil: Thanks a lot for your review! I'm worried about the channel rising waveform, could be an escenario where this has to be a problem?

Mine rises voltage in exactly same manner, it is correlated with relays switching, and I don't think that it will ever be a problem for home lab.
I have oscope and current probe, so I can take few measurements of voltage and current rise if You want to.

[thephil]

I own a UDP3305S, and I'm having difficulty understanding how the Over Current Protection (OCP) function operates on this device. My unit is running software version 1.10 and bootloader 1.04.

The Power Supply does not allow setting the OCP lower than the Current; it can only be set higher or equal. On channel 1, when I set it to 1A, it shifts into Constant Current (CC) mode when I draw more than 1A but does not activate the OCP. However, the OCP is triggered when I set it to 0.999A or 0.993A. This is likely a rounding error. And it never ever wants to switch channel off when OCP is set higher than current.

I can't understand why it doesn’t allow the OCP value to be set lower than the current? Am I misunderstanding how OCP should work?

As far as I know, OCP is constant current modes big brother: When the OCP threshold is met, the PSU will turn off the output in certain time – think fancy fuse. So if you have set a current limit it makes no sense to set the OCP limit lower than that, because OCP would shut off the output before CC can even kick in.

[pope]

Okay. Like someone said before: in Chipoteka web shop from Croatia this E model cost 390 EUR which is very good price

I can't find it on their website. I can only see the UTP.

[Doman]

As far as I know, OCP is constant current modes big brother: When the OCP threshold is met, the PSU will turn off the output in certain time – think fancy fuse. So if you have set a current limit it makes no sense to set the OCP limit lower than that, because OCP would shut off the output before CC can even kick in.

Totally understandable, but as You can see on photo attached in my previous post - my psu is set to 0.9A OCP and 0.9A current and it is running in CC without tripping OCP. But if I were able to set OCP lower that current I bet that it would shut down output instead going into CC mode.

I think that I should be able to set OCP lower that current output, it works this way in any other power supply that I have/had contact with. Implementation can be different (when which action happens).

What use case has setting OCP above current limit? When it will trip output?

[faktorqm]

Mine rises voltage in exactly same manner, it is correlated with relays switching, and I don't think that it will ever be a problem for home lab.
I have oscope and current probe, so I can take few measurements of voltage and current rise if You want to.

Hi sir! I'm sorry I can't help you with the OCP problem, as I don't have currently a unit on my hands.
If you don't mind, it will be awesome if you can take some measurements of the voltage rise. Not just for me, it's good to compare vs the unit that "thephil" already has.
Reagarding the question if that behaviour could be a problem, I assume that if you connect the power supply to a PCB with proper power filtering and so on, those 30msec until the power supply gets stabilized don't will do any harm. I assume with a bunch of capacitors it has to be cleared.

Thank you for your time! Regards!

[thephil]

Totally understandable, but as You can see on photo attached in my previous post - my psu is set to 0.9A OCP and 0.9A current and it is running in CC without tripping OCP. But if I were able to set OCP lower that current I bet that it would shut down output instead going into CC mode.

I think that I should be able to set OCP lower that current output, it works this way in any other power supply that I have/had contact with. Implementation can be different (when which action happens).

What use case has setting OCP above current limit? When it will trip output?

I guess, if you want the PSU to trigger OCP immediately when the limit is reached, don't set a CC level but only OCP. That should do what you want.

I guess having both activated, OCP will only trigger, if a large over current occurs and CC does not manage to contain it in time. In my tests I manged to reliably trigger OCP even when it was at the same level as CC. So maybe it depends on the exact conditions?

I found a page where Keysight explain their OCP behavior and it says that OCP will not trigger on "... short current spikes and other acceptably short overloads ...". (https://edadocs.software.keysight.com/kkbopen/how-does-over-current-protection-ocp-work-620692888.html)

[faktorqm]

On this video review it states that OCP will automatically go in CC mode (2:40 aproximately)



So I suppose it is the expected behaviour. Latr in the video it shows something called "monitor mode" (4:20 aprox) and when the setting is reached the output goes off. Maybe is that what you are looking for? Regards!

[Xandr]

Hello!
I also ordered this power supply for myself.
Where did you find the last firmware under it? I looked on the site - there is no 1.10

[Xandr]

Hi,

Yes, I got the following url for downloading the firmware image (v1.10) https://25628395.fs1.hubspotusercontent-eu1.net/hubfs/25628395/Instrument%20%20FIRMWARE/UDP3305S%20Update.rar. I don't know if/how long the link will last. As described in my blog post(http://techbotch.org/blog/lab-power-supply/index_en.htm), the update worked fine on my UDP3305S. I have no Idea if the same image is also valid for the UDP3305S-E or if that would brick the device.

• Unpack the *.rar file to get the firmware image UDP3305S.bin.
• Put the image into the root folder of a FAT32 formatted usb thumb drive. Do not change the filename.
• Turn off the power supply.
• Insert the usb drive into the usb port on the back of the power supply.
• Press and hold the UTILITY button and turn on the instrument.
• Now the update process starts.
• Once the update has finished turn the supply off and on again.
• Done.

Hello!
Where did you get a new firmware, ate no secret?
On the official website I did not find anything.
I also have their own multimeter 8805, I would like to update it.

[thephil]

@Xandr: the link to the firmware file is literally in the post that you quoted.

So far, UNI-T appears not to provide the firmware for the PSU for download on their official homepage – only the PC software.

[tonyalbus]

Had contact with UNI-T support and they now have
Latest 1.10 firmware now on the official website available for download.
it is one zip file with both the S and S-E file and manual and a start of a releasenotes

Great tests by Phil on his blog btw, thanks Phil

[tonyalbus]

Testing firmware 1.11 there OCP can be set before CC, so as a user you can decide which kicks in first.
same for CV and OVP.. which now brings a new thing.. that when OVP left unintentionaly at low value .. you outputs go off
but then you just switch off OVP or set it correctly.
will update when release on the official website.

[thephil]

Excellent –  it appears gentle nudging actually worked!

WRT the new firmware version: Did they add a normal tracking mode that allows for joint control of two channels, yet?

[tonyalbus]

Here it is:

https://www.tonyplaza.nl/download/YT0376/Firm1_11.zip

Upgrade method:
1. Select the upgrade file according to the model and put it in the root directory of the FAT32 format U disk (the file name cannot be modified);
2. Insert the USB flash drive into the machine to be upgraded (power off);
3. Press and hold the "UTILITY" button to turn on the computer and start the upgrade;
4. After the upgrade is completed, manually restart the machine.

V1.11 update:
Strategy for changing the output setting value and protection value: The output setting value can be made greater than the protection value.

V1.10 update:
1. Optimize SOCKET connection mode;
2. Solve the bug of occasional loss of sent data in SOCKET connection.

V1.09 update:
1. Add SOCKET connection mode, the connection port is 5025;
2. Optimize network connection.

V1.08 update:
1. Improve SCPI standards;
2. Add memory-related communication commands;
3. Optimize the local file manager and display the applicable channels of this list file and delayer file before the file name.

V1.07 update:
1. Add large font display mode.

V1.06 update:
1. Add power-on output function.

V1.05 update:
1. Added new communication commands to adapt to the NeptuneLab platform;
2. Added German to multiple languages.

V1.03 update:
1. The time resolution of timer and delayer is upgraded to 0.1 seconds.
2. The change strategy is: when the output setting value is greater than the reasonable value, the current value will not be changed.
3. An "error status" is added to the list output running status. When the output value set by the list is greater than a reasonable value, an error will be reported.
4. Add a shortcut for setting UI language.

[faktorqm]

I'm seeing it about 500€ in Aliexpress for Europe. Good price I think!

[audiotubes]

I bought mine from eleshop.eu for 449 euro + VAT. After several orders, I can recommend the shop confidently. They answer email quickly and ship immediately.

Mine's still in the box due to some scheduling problems. Tomorrow a new bench arrives and by the weekend the chaos should have diminished entirely