SPD3303X-E (unmodified) - curious behavior when outputs are on - Page 1
Forum section: electronics / testgear

author: MartyMacGyver
author_rank: Regular Contributor
timestamp: January 15, 2019, 04:37:50 am
content: I just got my SPD3303X-E (SW version 1.01.01.02.05 (latest!), HW version V3.0 (latest??))Out of the box,with no loadand with all voltages and currents set to 0.00, and outputs OFF, CH1 and CH2 say they are in CV mode.If I then turn all the outputs ON, CH1 goes immediately into CC mode, while CH2 stays CV. Both still show 0V at 0A out.If I set them both to some low voltage (not necessarily the same voltage) CH1 will stay in CC mode, 0V at 0A out, but CH2 will slowly seek the set voltage in CC mode, then switch to CV (after a few seconds it ends up at the target voltage at 0A).I do notice that if I set CH1 V to, say, 1 V (or really anything > 0V) and set some current, it will switch to CV and rise to that set voltage. CH2 will do this with with 0.00A.First question: Can anyone else confirm similar behavior?Second question: is this normal? Again, this is with no load (about to try some load testing now).(Seems CH2 will sometimes do this if CH1 is off, but not reliably. CH3 doesn't seem to affect any of this.)I should add that under load it seems more normal, though I'm still getting used to using the different modes. The channels are in independent mode.

author: tautech
author_rank: Super Contributor
timestamp: January 15, 2019, 11:34:57 am
content: Entirely normal. Just use it.Consider why it's shipped set like that. If controls were set to max there'd be complaints that the PSU blew things up when first connected.Adjust to the V you need then A to some reasonable value then turn the channel ON and any current draw above SET will shift the PSU into CC mode.A little time using it and you will appreciate this behavior.

author: ggchab
author_rank: Frequent Contributor
timestamp: January 15, 2019, 12:02:18 pm
content: With a setting of 0A, a small leakage current may trigger the "CC" mode. There may be a slight sensitivity difference between the 2 channels.

author: MartyMacGyver
author_rank: Regular Contributor
timestamp: January 16, 2019, 01:51:49 am
content: Quote from: tautech on January 15, 2019, 11:34:57 amI didn't expect it to be set to max or anything - I just wondered why, when set to 0V 0A, CH1 always powers on into CC mode and CH2 always powers on into CV mode.Quote from: ggchab on January 15, 2019, 12:02:18 pmThis is why I wondered if this indicates a fault of some kind. Sounds like it may be fine.I did check the output voltage and current with my Fluke and the channels differ very slightly, which begs another question:how do you calibrate this device?

author: tautech
author_rank: Super Contributor
timestamp: January 16, 2019, 02:55:30 am
content: Quote from: MartyMacGyver on January 16, 2019, 01:51:49 amDid it come with a Cal cert and does it look in order ?The calibration equipment used at the factory will be listed on the Cal cert.Typically it's a precision calibrator coupled to a PC running a script that performs an automated Cal process and that's an entirely 'closed case' process.

author: MartyMacGyver
author_rank: Regular Contributor
timestamp: January 16, 2019, 09:28:20 am
content: Quote from: tautech on January 16, 2019, 02:55:30 amYes - it just says an electronic load and digital multimeter were used. No mention of a particular calibrator or how the process works. That's why I asked.

author: tautech
author_rank: Super Contributor
timestamp: January 16, 2019, 09:55:39 am
content: Quote from: MartyMacGyver on January 16, 2019, 09:28:20 amI honestly thought there was more than that. I'll get one out for a look as I don't remember ever studying a PSU Cal sheet.

author: tautech
author_rank: Super Contributor
timestamp: January 16, 2019, 10:27:10 am
content: OK so here's the Cal sheet gen:DMM: 34401A = KeysightE-load: IT8722......Google....= ITECHSN#'s and Cal expiry dates included.So one might expect there's a Cal mode you place the SPD3000X-E into OR do the level adjustments via some secret SCPI commands.Anyone want to do a mem dump and have a hunt for them ?OR as I surmised earlier, the DMM and E load are controlled by a PC script and perform a closed box calibration.Hmmm, there's no service manual for any of the SPD's.....in Siglent's other equipment the Cal procedure is outlined in service manuals......but a hunt reveals a post I made a couple of years ago about Cal procedures:https://www.eevblog.com/forum/testgear/siglent-technical-support-join-in-eevblog/msg986796/#msg986796

author: Rerouter
author_rank: Super Contributor
timestamp: January 16, 2019, 07:25:36 pm
content: better than a mem dump, grab me the system app and I can probably figure it out for you.A command you can probably use as a starting point is "printcali" which should print the current calibration.not to mention if the calibration is anything like the scopes and spectrum analysers, there will just be a .txt file buried in the usr directory with the calibration info.

author: MartyMacGyver
author_rank: Regular Contributor
timestamp: January 17, 2019, 04:14:15 am
content: Quote from: tautech on January 16, 2019, 10:27:10 amI don't think I have any way to log into this directly.I successfully converted from X-E to X today (via USB), and the slight difference between setting and reality is more noticeable with the extra digit, so being able to at least match the channels up a bit better would be nice.And as always, it's good to know how to maintain the equipment yourself when possible (in the modern world where trimpot settings are long gone...)Edit: assuming there is any way to effect a tweak manually (even if it's tweaking cal values slightly - the ability to un-tweak being handy in absence of a full lab for said calibration).

author: tautech
author_rank: Super Contributor
timestamp: January 17, 2019, 05:00:40 am
content: Quote from: MartyMacGyver on January 17, 2019, 04:14:15 amWork with member Rerouter on trying to discover the adjustment methods, he's pretty slick at examining the undocumented SCPI commands from within Siglent gear.

author: MartyMacGyver
author_rank: Regular Contributor
timestamp: January 17, 2019, 05:43:45 am
content: Quote from: Rerouter on January 16, 2019, 07:25:36 pmI'm not sure how I'd go about doing this... unlike the other things I've modded, I didn't need to telnet into the PSU to apply the enhancement. Thoughts?

author: Rerouter
author_rank: Super Contributor
timestamp: January 17, 2019, 09:17:32 am
content: There are 2 scpi commands that come to mind. First is from the scope hacking thread. Reply 85.https://www.eevblog.com/forum/testgear/unlocking-siglent-sds1104x-e-step-by-step/?allIf that works you should be able to telnet in and grab it. Otherwise I take a shot in the dark that its similar enough to the scopes to work and you try "SHELLCMD cp -r /usr /usr/bin/siglent/usr/mass_storage/U-disk0/"This should copy everything in the usr directory to a flash drive. You will need to insert one. If it works then there will be an .app file under the siglent directory.

author: MartyMacGyver
author_rank: Regular Contributor
timestamp: January 17, 2019, 11:42:01 pm
content: Quote from: Rerouter on January 17, 2019, 09:17:32 amThis power supply doesn't even *have* a USB port for a flash drive. It'll connect to a PC via USB (or a network via ethernet) but that's all.

author: tautech
author_rank: Super Contributor
timestamp: January 17, 2019, 11:47:04 pm
content: Quote from: MartyMacGyver on January 17, 2019, 11:42:01 pmUse NIVISA Runtime for the connection driversAND install it first.Then EasyPower will then connect seamlessly and you can use the SCPI console within.

author: MartyMacGyver
author_rank: Regular Contributor
timestamp: January 18, 2019, 07:38:33 am
content: Quote from: tautech on January 17, 2019, 11:47:04 pmWhen I enter `SHELLCMD telnetd -l/bin/sh -p9999` and press Query, I get a beep (which it seems to only do for invalid commands, the other commands, the output of which is shown in the attached image, seem to work fine.)Without a place to even plug a flash drive in, though, how is this command supposed to be effective even if it works (not that it appears to)?

author: BillB
author_rank: Unknown
timestamp: January 18, 2019, 01:13:55 pm
content: I don't know that anyone has successfully started a telnet session with the SPD devices. I don't believe SHELLCMD works on the SPDs, and it certainly isn't for a lack of trying.

author: tv84
author_rank: Super Contributor
timestamp: January 18, 2019, 02:34:07 pm
content: Quote from: MartyMacGyver on January 18, 2019, 07:38:33 amYou can't do that.The SPDs only have one "application" running. They don't have a filesystem, shell, etc.Look at the FW contents here:https://www.eevblog.com/forum/testgear/siglent-ads-firmware-file-format/msg1335892/#msg1335892BTW look at these commands:https://www.eevblog.com/forum/testgear/lists-of-siglent-scpi-commands/msg1793117/#msg1793117I think they cover all the SCPI commands possible in the unit. (It should be similar to the X unit.)

author: MartyMacGyver
author_rank: Regular Contributor
timestamp: January 18, 2019, 08:53:26 pm
content: Quote from: tv84 on January 18, 2019, 02:34:07 pmI looked at that and started toying around with the commands. Any idea what "Factory mode" is? I've switched it on and switched it off, but I'm not sure what it means.Now that I know what the calibration commands ought to look like, I found a post on another forum that delves into how SCPI calibration works for similar devices:https://www.diyaudio.com/forums/equipment-and-tools/281868-source-firmware-software-programmable-power-supply-post4503727.htmlNot sure which of these will work or how well, but I should have enough equipment to at least attempt to get CH2 to match CH1 in calibration if the CAL commands actually work.If the CAL commands require a password though, I'm stuck there.

author: tv84
author_rank: Super Contributor
timestamp: January 18, 2019, 09:59:42 pm
content: Quote from: MartyMacGyver on January 18, 2019, 08:53:26 pmNo idea...The commands don't have password AFAIK.

author: MartyMacGyver
author_rank: Regular Contributor
timestamp: January 19, 2019, 01:44:22 am
content: Since this thread has wandered from my original question, I've posted it as a new (detailed) topic here:https://www.eevblog.com/forum/testgear/how-to-calibrate-siglent-spd1000x-spd3303x-spd3303x-e-series-power-supplies/