GW Instek GPP-3323 PSU fan noise on idle - Page 1
Forum section: electronics / testgear

author: kakci
author_rank: Newbie
timestamp: May 07, 2019, 10:37:40 pm
content: Hello!I'm planning to buy a PSU and i could find lots of infos about the Rigol and Siglent current models.Also I checked the GPP-3323 but sadly not much review or teardown about that model exists on the net.I'm especially interested in the noise factor (cooling fan), how loud is it on idle state?If any1 could check it (or even document it) on the Instek GPP series I would be greatful.Thanks.

author: er12
author_rank: Newbie
timestamp: May 12, 2019, 02:32:03 pm
content: Hi,I bought a GPP-4323 last month. The fan was a nice surprise !Without load the fan noise is very low, much quieter than my oscilloscope for example (GDS-2204E) !The built quality is really good, an ADUC7060 with an ADR03 reference for each channelThe UI is very nice too.

author: kakci
author_rank: Newbie
timestamp: May 13, 2019, 08:29:53 pm
content: Thank you for your help and the teardown pictures. So would you recommend it if you would need to run it under small load (< 500mA) overnight in your room?

author: er12
author_rank: Newbie
timestamp: May 15, 2019, 10:04:15 am
content: Hi,I did the the following test : channel 1 : 15v, channel 2 in load mode 250ma connected with channel 1, during more than 8 hours, the fan stay allways at the lowest speed.For the noise, it's the same level than a good quality PC power supply (Seasonic) with a low load.At a 3m distance, I can't hear the fan noise.

author: kakci
author_rank: Newbie
timestamp: May 15, 2019, 06:20:50 pm
content: Perfect thank you, Im gonna order the GPP 3323.

author: embedded_tom
author_rank: Newbie
timestamp: June 13, 2019, 01:15:32 pm
content: electrobob just did a nice review on the GPP-4323:https://www.electrobob.com/gpp-4323-power-supply-review/

author: KedasProbe
author_rank: Frequent Contributor
timestamp: January 07, 2021, 10:38:33 am
content: My GPP-3323 arrived today, (Europe Version with LAN)Delivered 10 days after order. (Eleshop 643€ all-in)To start: a few pictures (I will turn it on this evening after work, and warm up)

author: Hydron
author_rank: Super Contributor
timestamp: January 07, 2021, 11:56:27 am
content: Am interested in what your offset voltage/currents are. That's the most annoying thing for me, my worst channel is a little over 1mA out (though I have also noticed the aliasing that electrobob did when I was driving an oscillating load).edit: to be clear, I like mine, just nitpicking really!As for fan noise, I don't find it objectionable unless I'm drawing a lot of power from it and it spins the fan up, in which case I'm getting exactly what I should expect from a nice compact _linear_ supply - heat has to get out somehow!

author: KedasProbe
author_rank: Frequent Contributor
timestamp: January 07, 2021, 07:32:49 pm
content: The offset is about 1mA but when you just set it to 32V it shows 1.8mA read back, less when you reduce the voltage (in reality there is only a few µA current)Ch2 seems to be a little better than CH1.CH3 voltages are: 5.15V, 3.34V, 2.51V, 1.77V (stays the same with 10 Ohm load)A few Tests: (all measured with 10 Ohm as load, excluding DMM6500 in series)Set: 500mA DMM6500: 499.4mA CH1Meas: 500.1mASet: 2mA DMM6500: 0.85mA CH1Meas: 1.9mASet: 2.1mA DMM6500: 1.07mA CH1Meas: 1.9mA (trying to get as close to 1mA as possible)For lower than set 1.2mA the output is nothing, Off means -0.72µA on CH1 and CH2, on CH3 -0.076µAOff Open is -7.4mVOff Load 10 Ohm -0.15mVFirmware was version v1.06, March 2019, I upgraded to v1.12, March 2020Taking a screenshot fails, it hangs until I remove the USB stick. (writing an empty .BMP file)And yes it is silent with slow fan speed, it didn't run faster yet, I can't hear it when the fan of the DMM6500 is on.

author: Hydron
author_rank: Super Contributor
timestamp: January 08, 2021, 09:16:21 am
content: I think you're getting similar results to me - using it to source or measure small currents requires care and is not just set-and-forget. I guess this is why it isn't >1k EUR/GBP though, as the specs/features would otherwise suggest!I just wish there was a public calibration procedure, as it seems like some tweaking would help a lot with this. Sure it's in spec, but I bet they didn't have the right tongue angle during factory cal.The firmware does not seem to be encrypted btw, I'm just unfortunately clueless at reverse engineering software so it isn't a lot of help

author: KedasProbe
author_rank: Frequent Contributor
timestamp: January 08, 2021, 04:11:33 pm
content: I think the first mA are a bit unstable so I'm not sure if they even calibrate that point.But on the other hand if you want a small current source you may be better of putting it to 10V and set a 10kohm resistor in series.During the weekend I will do some more tests, maybe a video.Are you able to make screenshots? (not that I really need it, it's also a strange way of making screenshots)Did you ask them for a Calibration Procedure?(I will ask after they explained my issues, don't want to mix subjects too much)Edit:FYI I got this 'error' short on my screen during upgrade:

author: Hydron
author_rank: Super Contributor
timestamp: January 08, 2021, 04:38:10 pm
content: I did ask eleshop for the cal routine, they were like "what do you need that for?" and pressing further didn't help. Would appreciate if others have a go at getting it as well.As for screenshots, it _seems_ like it has crashed, but page 93 of the manual says the following:Code:In the target interface, press System button >F1 (Setting) > F5 (Hardcopy) button and rotatethe scroll wheel (Encode) to locate the targetinterface followed by pressing Enter key tosave screenshot. A confirm voice will soundwhen successful.And sure enough, the encoder and enter key do what they say, and it comes back to life with a .BMP on the USB drive root.

author: KedasProbe
author_rank: Frequent Contributor
timestamp: January 08, 2021, 04:43:27 pm
content: Maybe I need to wait longer, not sure, or try another smaller USB stick. (if I can find that)I also cannot find build date or calibration date of this unit, nothing has a date except the release date of the firmware and that was 2019edit, no I only get an 0 Bytes .BMP file.saving a SETSTV.STA file on it of 448bytes worked also .CSV works, so I don't think the problem is the USB stick

author: Hydron
author_rank: Super Contributor
timestamp: January 08, 2021, 05:46:59 pm
content: Mine GPP-4323 came with a newer firmware installed - V1.14, Oct 9 2020. Can only see V1.12 on their website however (always possible though that the newer version relates to production changes rather than anything the end-user sees).No obvious build date either, though it must at least have been powered up for an update after that Oct-9 date. While I ordered in October, I had to wait for a new shipment to arrive by air in November as they were out of stock, so a build date not long before I got it makes sense.

author: KedasProbe
author_rank: Frequent Contributor
timestamp: January 08, 2021, 06:16:13 pm
content: Yeah looks like I have one of the old first units since the 3 channel with LAN isn't bought much.I can still return it no questions asked I'm still in my 7 days.Did your screen had a screen protector? (mine didn't)

author: Hydron
author_rank: Super Contributor
timestamp: January 08, 2021, 08:25:09 pm
content: Quote from: KedasProbe on January 08, 2021, 06:16:13 pmNot 100% sure, but I don't think so.

author: KedasProbe
author_rank: Frequent Contributor
timestamp: January 09, 2021, 02:43:42 pm
content: Some On and Off graphs:Risetime (10%-90%) is about 20ms unless the CC kicks in sooner, can be 14ms.Falltime is max 700ms without load and decreases depending on the load, 10 Ohm is 14ms(see scope screenshots)Power consumption is about 16W and with the screen off it's about 1.5W less (on mains, not very accurate)Using 2.5W DC adds about 10W on mains (230V 50Hz)Using 10W DC adds about 30W on mains (doesn't increase fan speed, at least not immediately)Network commands in the browser works but is a bit slow.

author: KedasProbe
author_rank: Frequent Contributor
timestamp: January 10, 2021, 02:44:33 pm
content: Some extra test Output (CH1 and CH2)There is a load resistor present of 500 Ohm (Measured in power off 494 ohm, CH3: 938 ohm)To confirm I placed a 500 ohm load CH1, the results should be a falltime of half of the no load 700ms -> 350ms confirmed.Output capacitor size?Calculated based on measured falltime CH1: 0.700s/2.2/494ohm = 644µF (2.2 = conversion from falltime to Tau)Measured at 100Hz during power off:CH1 621µFCH2 649µFCH3 92.7µF (different for GPP-4323)So about 640µF parallel with 500 Ohm on CH1 and CH2Speed of OVP and OCP:Testing method: set it so you know OCP or OVP has to kick in when you turn the channel on.I tried only OCP, only OVP and both at the same time they resulted in the same result.Min 100ms Max 200ms before the output is turned off.That is longer than I thought it would be and I assumed with OVP it wouldn't even turn the channel on since it already knows what is going to happen, but it did turn it on like it had no idea that Set voltage was higher than OVP.Speculation:I don't think there is any hardware involved, checks the readback and then acts, if it just missed the last update it has to wait 100ms for the next one and then it takes 100ms to act.They do claim it is hardware OVP/OCP protection, I would like to see prove of that, 150ms is very slow for hardware reaction time, I would also expect the reaction time to be the same every time you do the same test.Quote(Technically this quote is always correct though)Also setting 0V CH1 gives about 1.8mV, with 10 Ohm 1.7mV(Channel off -7mV, with 10 Ohm -0.15mV)

author: KedasProbe
author_rank: Frequent Contributor
timestamp: January 22, 2021, 04:53:39 pm
content: The firmware version 1.16 (15 July 2020) replacing 1.12 (17 March 2020) is now available to download from their website.I'm still waiting for a response from GW-instek about the error message during firmware update to 1.12, the failure to take screenshots, some reaction about the OVP/OCP in there documents is less than 50ms, not 100ms+ and calibration/build date info.

author: samipetri
author_rank: Newbie
timestamp: January 22, 2021, 05:43:33 pm
content: Quote from: KedasProbe on January 22, 2021, 04:53:39 pmI got change log also when i asked GW why there is no new FW at their website.GPP_X323Version V1.14->1.15 Modify the problem that the secondary CPU cannot be upgraded by the main CPUV1.15->1.16 1. Modify the continuous boot exception caused by the removal of the special treatment of CH3 and the problem that the USB disk cannot be recognized when the boot is inserted2. Modify the issue of backlight hardware for the software compatibility. Note: After upgrading the software, the version before 1.16 cannot be upgraded

author: KedasProbe
author_rank: Frequent Contributor
timestamp: January 23, 2021, 03:19:37 pm
content: I did the update to 1.16 but it looks like it didn't do it correctly: shuts down too early I think, the update of 1.12 took much longer and had an end message. (the version shows 1.16 now though)Because I didn't want to miss an error on the screen this time I recorded it. (to send to GW instek)Looks more and more that there is something bad with my unit although it seems to work. (obviously I didn't try everything)https://youtu.be/iCOGoF51ncUQuoteP.S. You can hear the fan spin up and down, to stay on topic

author: KedasProbe
author_rank: Frequent Contributor
timestamp: January 23, 2021, 04:32:04 pm
content: Bonus Video while I was recording the firmware update:https://youtu.be/jTXdN6LOPTsEdit: Updated measured output of CH1 after warmup, output measured with DMM6500Code:import socketfrom time import sleepip_address_DMM = "192.168.0.211"s_DMM = socket.socket()s_DMM.connect((ip_address_DMM, 5025))ip_address_GPP3323 = "192.168.0.183"s_PS = socket.socket()s_PS.connect((ip_address_GPP3323, 1026))sleep(1)Channel = "1"Voltage = 0.0s_PS.send(("VSET" + Channel + ":" + str(Voltage) + "\r\n").encode()) # set voltages_PS.send((":OUTPut"+ Channel + ":STATe ON\r\n").encode()) # turn channel onsleep(5) # discharge without load (via 500ohm internal load)RBValues=[]Stepsize = 10 # 'mV'for mVoltage in range(0, 32000, Stepsize):s_PS.send(("VSET" + Channel + ":" + str(mVoltage/1000) + "\r\n").encode()) # set voltagesleep(0.5)s_PS.send((":MEASure" + Channel + ":VOLTage?\r\n").encode()) #VOUT1? includes 'V'RBVoltage = float(s_PS.recv(30).decode())RBValues.append([mVoltage/1000, RBVoltage])print(mVoltage/1000, RBVoltage)s_DMM.send("dmm.measure.read()\r\n".encode())sleep(0.4)with open('GPP-3323Readings.txt', 'w') as f:for item in RBValues:f.write("%s\n" % item)

author: KedasProbe
author_rank: Frequent Contributor
timestamp: February 13, 2021, 03:19:43 pm
content: I also measured the second channel it's clear that the two voltage measurements are almost identical, and are always a little too high.(this will even increase with a load and voltage drop on the wires)The voltage output is again not very smooth with 10mV steps but this time with CH2 the readback and the setting are more equally wrong.(meaning set and readback show little difference on the display)I'm still waiting for support from GW-Instek, they wait for the engineers to answer....It are slow default messages:QuoteThe engineer did say that the firmware update errors weren't supposed to be there but I guess that was a given...And it takes time before they realize that the USB stick is not the problem of the sheenshot failure. (I tried a few I even bought an old type)I made the settings & readback in reference to the output to make it less confusing. So positive error means they display more than what is on the output terminals.

author: KedasProbe
author_rank: Frequent Contributor
timestamp: February 14, 2021, 12:26:57 pm
content: Using the power supply as extra voltmeter?The resistance is about 100kOhm in load mode with channel off. (max. resistance is 1KOhm with channel on)It will show -.----- below 1.0V (since the load does not work lower than that)You do have a capacitance of about 400µF on it.In source mode the display will also be grayed out but it will always display 0.0000V

author: Hydron
author_rank: Super Contributor
timestamp: February 14, 2021, 05:13:52 pm
content: Should have my own DMM6500 in a few weeks, will run your script to get some more datapoints (with channels 3 and 4 in addition).Really hope they release the calibration procedure; while realistically the supply easily does what I need it to (especially given the addition of a Keithley 236 SMU for accurate low current sourcing/sinking, at least once I get some triaxial cables/connectors for it), it is super annoying to see the offsets at zero. Would be good to know what they mean by "Note: After upgrading the software, the version before 1.16 cannot be upgraded" too.Edit: Oh and by the way, while it won't display voltages below 1V you can still read them back via SCPI. I tried CC mode to discharge a NiMH to ~0.8V and that worked too.

author: KedasProbe
author_rank: Frequent Contributor
timestamp: February 15, 2021, 08:01:06 am
content: Nice, you will see the graph you have on DMM6500 is really useful compared to the graph view in the GPP-X323For the measurement I did set it to 1PLC and a filter of 5 averages.Put it on manual trigger and clear the buffer, first time you run it will give an error since it wasn't in remote control, second time you run it will be fine. (maybe I make the script better but it's not like I need it much)And indeed the zero offset is a bit strange to see.I don't mind the Voltage offset as much as Current Offset, you can't even tel if something is taking current or not.There is some leak current through the shunt because the higher the voltage set (without anything connected) the higher the current offset is, not sure if they forgot to compensate for that or just said it's within spec...P.S. I'm also thinking about setting the PS voltage with an DMM6500 app (touchscreen input) as experiment but I haven't tried the connection yet. (would allow some correction on the setting to get the right output)

author: KedasProbe
author_rank: Frequent Contributor
timestamp: March 16, 2021, 05:01:57 pm
content: About the USB stick not saving the screenshot:I asked for a working USB stick so we can exclude the USB stick as the problem.They agreed (but again slowly)It worked, so after some investigating by me:Format cluster size of 8192B is not supported, 4096B is supported. (you can check it with chkdsk in windows)The other questions/issues are still hanging.

author: Hydron
author_rank: Super Contributor
timestamp: March 16, 2021, 09:50:21 pm
content: Quote from: KedasProbe on February 15, 2021, 08:01:06 amI took some measurements for all 4 channels, see .csv files in the attached zip. I noticed that the script doesn't hit the final voltage value, fixed it for channels 3 and 4 but too late for 1 and 2 (and didn't want to run it again). Take a look at channel 3 in particular - I think I know my favourite for accurate output/readback voltage! Probably should test the current setting too (I don't expect it to be quite as good), but it will need to wait for another day.

author: KedasProbe
author_rank: Frequent Contributor
timestamp: March 17, 2021, 07:03:48 pm
content: Yes, I know the 32V wasn't in there I also noticed that after it but I didn't think it was important since it are 10mV steps.also you can go up to 33V.I made the same graph view with your data to make it easy to compare, yours is certainly (better) calibrated.edit: yes there is definitely something wrong with your channel 3, it doesn't match the spec sheet at all

author: Hydron
author_rank: Super Contributor
timestamp: March 17, 2021, 11:14:32 pm
content: Yeah I must say it was better than expected. I have no complaints about the gain calibration, it'd just be nice to have a smaller zero offset for very low current/voltage work (I now have a SMU which can cover most of that, but having more source channels is always handy).I'm doing a quick current test now, but it's an annoyingly noisy test when you're trying to work next to it (ends up dissipating quite a bit of power within the supply due to a large voltage drop at high output current). I'll probably finish off the testing when I'm not going to be next to it through the whole run! Also would be interesting to test the current regulation with a load voltage in addition to the ammeter + cabling burden voltage (use one channel for source, one for CV load mode at say 15V to stay under the 50W max dissipation limit at 3A output). That won't help the noise though!Could you share the code you're using to process the output and make the graphs? I was lazy and just threw my numbers into excel (a bit of an ugly manual copy/paste process), I should really brush up on my python but don't have a lot of time at the moment

author: KedasProbe
author_rank: Frequent Contributor
timestamp: March 18, 2021, 06:26:29 pm
content: I just cloned my excel tab and copy/pasted your columns.but it would be nicer if it was all done in python.

author: Hydron
author_rank: Super Contributor
timestamp: March 18, 2021, 07:58:56 pm
content: Hah, so you were just doing the same as well.Attached is the channel 1 test vs the DMM6500. X axis is in mA (forgot to setup proper units). Readback seems pretty good, but some issues with low-current setpoints (still well within the fairly loose spec though). I am wondering if it's actually from drift on warmup - when freshly turned on the supply output very close to 1mA when set to 1mA, but is drifting upwards, maybe they calibrated it without a warmup period?

author: KedasProbe
author_rank: Frequent Contributor
timestamp: April 03, 2021, 09:58:37 am
content: After again a few weeks of silence and sending a reminder (again) I got a response (about my firmware update problem and calibration question)They say if it's not more than 10mA wrong then it's within spec.I think they should change that to +100mA just to be sure I mean an ADC with 300 steps resolution is hard, that's more than 8 bit!And then they show me how it should look like (in their lab) a nice 0.0mA!! :it's only wrong when it's 100 steps more than 0.0mA.So a few speculations:- They have poor quality control.- The current readings drift a lot over time.There is some warmup drift but that settles down relatively fast, the current goes a bit closer to 0 during warm-up time. So it's not like they calibrated cold because then it would start correctly and move away from zero during warm-up.What I have seems more like oeps we forgot to calibrate that one.GW-instek Support:The slow communication with GW-instek with some person in between you and the engineer is certainly annoying.And due to the fact it's so slow they forget the information that I already gave them. (I fear I'm going to end up in a circle)It has been 3month since I first contacted them.I already made the joke to them that at this speed it will be out of warranty by the time you figure it out.Sure they apologize blablabla, change your actions!

author: Jan Audio
author_rank: Frequent Contributor
timestamp: April 03, 2021, 01:46:58 pm
content: I dont get it, the 4323 is +€20,-Maybe it was sold out ?And about the milliamps not going to zero, i also have that on channel 2,3 & 4.Why is channel 1 perfect 0 milliamp and the rest not ?, it shows values without anything connected.I dont care, did not have to buy any rigol or siglent, then you can expect way more troubles.About the fan-noise, it is hearable from the side, if i sit in front of it i dont hear it.

author: KedasProbe
author_rank: Frequent Contributor
timestamp: April 03, 2021, 05:31:49 pm
content: Quote from: Jan Audio on April 03, 2021, 01:46:58 pmThere is even a promotion, for 3 months:https://www.eleshop.nl/gw-instek-gpp-4323-programmable-power-supply-lan.htmlThe 3 channel has some easy USB powered specs compared to the 4 channel so it's not like you get the 3 channel version with an extra channel. (so your USB powered DUT can be powered on at the same time as the other channels)It doesn't have voltage or current measurement on the USB channel though, I miss that but maybe it was so bad they decided to remove it. (if you can't see if your DUT is taking power or not based on the displayed current ....)

author: Jan Audio
author_rank: Frequent Contributor
timestamp: April 04, 2021, 03:35:57 pm
content: Quote from: KedasProbe on April 03, 2021, 05:31:49 pm4323 also has a USB thing, i cant find the difference.Channel 3 on the 3323 is only 1.8/2.5/3.3/5.0V on 5A, to me its a 2 channel PSU.You going to fry your device under test ?

author: KedasProbe
author_rank: Frequent Contributor
timestamp: April 08, 2021, 07:03:41 am
content: Channel 3 on the GPP-3323 has two types of output connection:The terminals and an USB connection.The USB connection has an 3A OCP and the terminals have a current limit of 5A. (fixed unfortunately)If you decide to use both connections at the same time (probably not), that is possible but you have to make sure that the sum of the current doesn't exceed 5A (theoretically you could go to 5A+3A)They really missed out on having a decent USB power monitor feature.The USB connection on the GPP4323 is there to put your USB stick, not for power delivery.

author: Hydron
author_rank: Super Contributor
timestamp: April 08, 2021, 08:15:36 am
content: I had a look at the <4 channel options when buying my GPP-4323 (especially as they were available without any wait, unlike the LAN equipped 4323 at the time), however the value seemed pretty poor compared the 4 channel version. The 3rd and 4th channels are unusually fully-featured and useful on the 4323 - there are plenty of occasions where you need full current/voltage limit control/readback (often not offered on "aux" channels) but 5 or 15V @ 1A is sufficient. I've certainly already found it handy for circuits with 3-4 power rails.4323 USB port can run low power 5V items (I assume up to the 500mA USB spec, though I've not tested that high), but as mentioned is really intended just for USB sticks. The screenshot function is a bit useless as others have found, but it does seem to at least work when I tested on mine, though I don't see myself using it often.

author: nctnico
author_rank: Super Contributor
timestamp: April 08, 2021, 10:27:12 am
content: Quote from: KedasProbe on April 08, 2021, 07:03:41 amNevertheless it is really handy to power an active probe or something similar. Many non-brand specific active probes are USB powered nowadays.

author: Hydron
author_rank: Super Contributor
timestamp: April 08, 2021, 12:19:58 pm
content: Quote from: nctnico on April 08, 2021, 10:27:12 amAgreed, hence the "4323 USB port can run low power 5V items (I assume up to the 500mA USB spec, though I've not tested that high)" comment - I have used a Micsig DP10013 on it.I am slowly accumulating test equipment with USB ports, up to 4 now with scope, this PSU, my new DMM6500 and a SA/VNA - a lot handier than when only the scope had a USB port and I was always needing to dig out phone chargers etc for powering a probe at the same time that I needed to use a USB stick in it.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: April 08, 2021, 12:40:35 pm
content: Quote from: Hydron on April 08, 2021, 08:15:36 amI,m telling you i run out of channels already with my first project.So handy, 12v 6v 5v 3,3v now i need more, 2,5v and 4,66 volt.Seems you can stack em very easy.

author: Hydron
author_rank: Super Contributor
timestamp: April 08, 2021, 01:22:19 pm
content: Quote from: Jan Audio on April 08, 2021, 12:40:35 pmThis is why I also have a triple channel supply (3rd channel only 3.3/5V), a 400V capable single channel supply and a SMU on the benchSeriously though, the GPP-4323 is a very conveniently small form-factor for the number of channels it has, this was a big reason why I bought it (and retired my old single-channel linear supply).

author: KedasProbe
author_rank: Frequent Contributor
timestamp: April 08, 2021, 05:23:41 pm
content: I connected my phone to both USB connections both gave about 500mAIt's strange that the USB power connection (up to 3A) only gives 500mA If you know that if I connect my phone to an USB power plug it takes 1A.

author: nctnico
author_rank: Super Contributor
timestamp: April 08, 2021, 10:52:50 pm
content: Quote from: KedasProbe on April 08, 2021, 05:23:41 pmNo. That is precisely according to the USB charging specs! A standard host port is specified to deliver 500mA maximum. Only charging ports deliver more current but the way this happens depends on whether it is charge-only or a combined host / charging port.

author: KedasProbe
author_rank: Frequent Contributor
timestamp: April 09, 2021, 06:59:33 am
content: Well that is exactly why it is strange, it's not a host port it's a power port.a few possibilities:- They configured the USB power socket wrong, an 3A power socket should obviously not be limited 500mAor- There isn't 1 standard about how the device should recognize the power port so maybe this device doesn't recognize it correctly, other devices may recognize it...

author: Hydron
author_rank: Super Contributor
timestamp: April 09, 2021, 08:37:21 am
content: Quote from: KedasProbe on April 09, 2021, 06:59:33 amVery much this. USB charging has been a mess foryearsdecades with probably dozens of different standards, and while in theory if everyone just used the relatively recent USB PD spec the problem would be solved, it's over 600 pages and isn't something you can do for a few cents with some simple passives. In the meantime you can only rely on 500mA (and even that is meant to be after some negotiation with the host I think, just everyone ignores that bit).

author: nctnico
author_rank: Super Contributor
timestamp: April 09, 2021, 03:01:47 pm
content: Quote from: KedasProbe on April 09, 2021, 06:59:33 amActually there is a very detailed standard. Check the USB2.0 charging standard from usb.org .The additional USB port (which is basically parallel to an output channel) isn't an official USB port so there is no surprise it doesn't adhere to the standard. It is just there for convenience.

author: KedasProbe
author_rank: Frequent Contributor
timestamp: April 09, 2021, 05:14:48 pm
content: It wouldn't be convenient if all USB devices are limited to 0.5A, why wouldn't they identify it as charging port, if they didn't it seems like a design mistake to me.Anyone with a Raspberry Pi 4 that can test if it delivers enough power?(although this may be another special case)Powering the Raspberry Pi was in their marketing material.

author: nctnico
author_rank: Super Contributor
timestamp: April 09, 2021, 06:46:59 pm
content: Quote from: KedasProbe on April 09, 2021, 05:14:48 pmYou can always put a circuit in between to make the USB power output port identify itself as a dedicated charger or a charging downstream port. But that also requires to set the PSU accordingly (voltage / current limit). Having this circuitry inside the PSU limits the number of scenarios you can test.

author: KedasProbe
author_rank: Frequent Contributor
timestamp: April 10, 2021, 10:00:40 am
content: If I have to add another circuit in between then there is no point having the 3A USB port connection on the power supply.From what I read a charging port should have a resistance of less than 200 ohm between D+ and D-(this may be a doable mod)edit some extra info for Samsung and Apple 'Standards'https://obddiag.net/usb-power.html

author: KedasProbe
author_rank: Frequent Contributor
timestamp: August 07, 2021, 01:05:55 pm
content: I noticed that the measured current is also depending on the max set current on my CH1.Seems like a software bug since there is only 1 current range so there is no reason the measured value could/should change. (open circuit)

author: nctnico
author_rank: Super Contributor
timestamp: August 08, 2021, 07:35:01 am
content: You set 1A and 0.015A. Likely this PSU has two current measurement ranges and depending on the current limit, it switches between those.

author: ITTSB.Europe
author_rank: Contributor
timestamp: August 08, 2021, 11:44:12 am
content: It seems that some one feels bored to read in detail the USER Manual.Also it is forbidden by law, any similar power supply to supportSamsung high speedcharge.In general, the analog part of these PSU, this has roots to Japanese Kenwood PD35-10 (old series) and similar.The new control panel this is fantastic.Few months back I talked with the headquarters, and asked if they have similar model with user selected Fan-OFF mode at low current output?They haven't think of such a requirement, but when such a feature will be added, then I will be motivated to rethink of getting one of them too.