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| Custom Firmware for gpp 4323? |
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| TmaxElectronics:
So I've teated myself to a gpp4323 power supply last year and have been pretty happy with all but one thing about it: the slow output current update rate without and low pass filtering. I often built things that have small power peaks and almost no draw otherwise and with them the current display is just completely useless. Has anybody looked into writing some custom firmware or modifying the existing one to make the update rate faster or at least add a low pass filter? It would be a stretch unless somebody reversed the code somehow, but with the thing running on an arm CPU there might be a chance for using fairly standard reversing tools (provided one could read out the flash somehow). Otherwise it would pretty much be down to writing ones own software for the thing which i guess in not viable with all the features that thing has. The CPU is an nxp lpc1788fbd208 incase somebody is wondering. EDIT: I just spend some more minutes on the web and got the firmware file from the gwinstek website. I've attached it to this post incase somebody who knows more about ghidra or ida pro wants to have a look at it. Binwalk and a quick look with strings seems to suggest its an uncomressed flash image and the size matches that of the MCUs flash memory. (original extension was .bin) |
| nctnico:
A PSU is the wrong tool for profiling peak current consumption. You'll never get an accurate reading. You'll need a current consumption profiling tool. This can be as simple as a current shunt resistor which you measure using an oscilloscope. However, the display on a PSU will always show the average current. |
| TmaxElectronics:
--- Quote ---However, the display on a PSU will always show the average current. --- End quote --- Well thats the issue... the meter on the GPP (at least mine) does not. It only shows whatever the ADC read at the time. And I'm not trying to get some super accurate power reading here or anything, I just want to get a rough average instead of a dice roll every time the display updates ;) Especially since the front end has a 100uA resolution. |
| nctnico:
--- Quote from: TmaxElectronics on April 08, 2022, 11:05:15 pm --- --- Quote ---However, the display on a PSU will always show the average current. --- End quote --- Well thats the issue... the meter on the GPP (at least mine) does not. It only shows whatever the ADC read at the time. And I'm not trying to get some super accurate power reading here or anything, I just want to get a rough average instead of a dice roll every time the display updates ;) Especially since the front end has a 100uA resolution. --- End quote --- In that case a you can try to read the PSU remotely and average the values. If your PSU has the network adapter, this could be of interest: https://www.eevblog.com/forum/testgear/open-source-lxi-tools-v2-0-released/ |
| alm:
--- Quote from: nctnico on April 08, 2022, 10:56:29 pm ---A PSU is the wrong tool for profiling peak current consumption. You'll never get an accurate reading. You'll need a current consumption profiling tool. This can be as simple as a current shunt resistor which you measure using an oscilloscope. --- End quote --- There are specialized power supplies, like the Keithley 230x and HP/Agilent/Keysight 663xx battery simulators, that are designed to measure peak power level with a bandwidth in the order of a few (10?) kHz. They might be better tools in some way than a scope + shunt with a better dynamic range and a lower output impedance. Your general purpose power supply is indeed very unlikely to sample fast enough, however, and no firmware modification is going to help this. |
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