ET5410 Electronic Load mod: add external sense

[cybermaus]

Small mod, just mentioning it.

The ET5410 already has small internal sense wires from the board directly connected to the banana lugs, so they were easily intercepted.
I did not even cut them, but instead took out and rerouted the small 2-pin plug on the PCB, and connected those via a slider switch, see photo.
BTW: I forgot to take pictures of the inside, and I do not want to open it yet again, but its simple enough:

The sense wires each go via 2-pin plug a pair of 100K precision resistors (so 200K each) to a TL072 OpAmp with a 30K /4K resistor over it to make it into a voltage scaler;
30K or 4K switched by DPST relay, which is controlled by the range setting of the device, high 150V range presumably choses the 4K.
Alas no reverse polarity protection on the now separate sense wires, I am now wondering if I should have shorted the middle of the 4 100K resistors with a diode. After all, the TL072 can only stand -0.3V


Originally, I had some worry on how the device would respond if there was accidentally no voltage on the sense wires. I worried about software hanging with "divide by zero errors", but it is behaving perfectly:
- CC mode: it does not care, just keep drawing the current, but V and W display go to 0, and back up when reconnect
- CP, CR and CV mode : the device just stops drawing current, but does not hang, Reconnect, and it starts up again.
Even repeatedly switching from internal to external sense seems to not bother the device.

Oh, and while you are in there, put a  felt pad on he support screws of the main heatsink. They protrude a little, and if someone dents the sides, they may make contact to the V+ input.


Comparing to video's of the Kunkin I have seen, I like very much that I can change the CC setting while the load is on.
Also I did not observe any startup instabilities, and the load seems to work properly (on my supplies) down to 0.2V

[Hydron]

Good to see someone having done this successfully - I'm looking at buying the 500V version of this load (or alternatively the similar looking DCL6104A) and doing the same.

Have you got any resistance between the main and sense terminals? A couple of hundred ohms or so would ensure that even if the switch was in the wrong position the supply will still see the voltage at the terminals with minimal error (200/100k = 0.2%) but should still be large compared to wiring resistance if the sense function is used (if the wire is 100 milliohms 0.1/200 = 0.05% error, not sure if that's a completely correct equation but it will be small regardless). Could put a parallel diode to clamp any voltage on said resistor too (in case the main connection goes open) though a polyfuse in series would be advisable as well to protect the diode if high currents are to be used.

Finally, do you have any pictures of the inside of this unit, especially the sense section? Would be interested in seeing them. And have you checked any of the more advanced features (e.g. the Dynamic load) - does it meet or at least let you set it according the datasheet specs (e.g. 1.5A/us slew rate - I recall someone complaining about this being unavailable on this or a similar load)?

[cybermaus]

On the resistors, I considered that at first, expected to do so.

However, I  started rethinking this when noticed these were high-precision resistors, and the OpAmp was setup as a voltage divider.
So any additional resistor, or any resistor shunting between main and sense, would bring this voltage divider off balance, and affect precision.

I did some serious thinking on how to make a resistor network or even considered adding a 2nd opamp as voltage buffer.
But between the wanted precision, the fact I could not re-calibrate, and the fact it needs to work over the entire 0-150V, I could not work it out

So I decided to go for the low-tech solution. A DPDT slider switch. And as stated, it works well.
Also, the ET5410 matches my "best" multimeter precisely. Both before and after I added the switch.


On the slew rate specs, I did not test.
But I did at one point use it as a CR to test how some IBGT were working and managed to keep up on the emulated resistor quite well on a 20KHz PMW signal.


Edit: Oh, and as to a very low resistance like you state (100 ohm. Which would make the OpAmp 30K/230K turn into 30K/230K1 so only 0.04%
Yes, but. if I would cross over my lines, I'd have the full voltage over 100 Ohm, theoretically 150V and thus 225W, practically for me 24V so 6W
The resistor would evaporate. So rejected low ohm. And high ohm would as mentioned, would affect measurement.

[Hydron]

Edit: Oh, and as to a very low resistance like you state (100 ohm. Which would make the OpAmp 30K/230K turn into 30K/230K1 so only 0.04%
Yes, but. if I would cross over my lines, I'd have the full voltage over 100 Ohm, theoretically 150V and thus 225W, practically for me 24V so 6W
The resistor would evaporate. So rejected low ohm. And high ohm would as mentioned, would affect measurement.

Yes this is indeed an issue, which is why I suggested a diode clamp and a polyfuse - unfortunately this is extra complication so fair enough if you'd prefer just to rely on remembering to have the switch correct.

The main issue here is the fact that the voltage and current range is so high - a power supply with sense may only supply say 5A or 30V - this can be covered either with a low value resistor (bypassed by a diode) or a higher value resistor with no diode (accepting a moderate accuracy loss if the sense switch is on but no sense leads connected). 150V/30A is trickier though, a resistor big enough in value to not smoke would cause major inaccuracy if the switch was in the wrong position, while a clamp diode would need to also deal with a big power dissipation if a lot of current were drawn.

I might have a quick look at how the itech supplies do it as I've got one handy at work (hopefully it's obvious).

Thanks for the IGBT testing info - if it handles 20kHz OK that's better than expected! Did you take any pics btw when doing the mod?

[cybermaus]

Well, yeah. Though the rate cannot be adjusted (I did search for that) but was better than I expected.
20KHz worked, though I did see a little slow responce in the square wave. If I remember, at 10KHz the resulting wave was pretty much square, on about 3 Amps.
But this is in no way precise measureing


Anyway, I would just go with the slider switch.
Only, as stated, next time I open it, I will add a reverse protection diode, in the middle of the 4 100K resistors.
So it is 2x 100K away from input, no need for a fuse. And also still 2x 100K away from OpAmp, so reverse leakage current has less impact.


Edit: Simulation shows I should just add a very generic diode like 1n4148  as protection  completely on the inside, directly between + and - of OpAmp. While it is closer to the OpAmp, the voltage over there is so low, leakage is in the pA range (in simulation) so that it would not affect the measurement. Where is in the middle of the 2 100k resistors, it gets actual double digit voltages, and leakage does affect outcome (only a little, but more).

[Hydron]

So I checked the Itech load and it uses a relay to switch to the sense inputs - you have to enable it in a menu then use the terminals on the back.

[cybermaus]

Some testing showed that in dynamic CC mode the ET5410 has a highest slew of 4Amp in 10mS. So 0.4A/ms
Which is so out of whack with the specs (1.5A/uS) that I wonder if I am doing something wrong
Am I misinterpreting how this slew rate works?

The difference with the previous mentioned 20KHz was, this was where the CR mode responded to an external AGBT switching, whereas here it is the load itself that drives in a dynamic mode: 10ms .1Amp, 10ms 7 Amp

Or maybe my power supply is the limit.
I will test more tomorrow.

[cybermaus]

@Hydron: So, on your question regarding transient rise times.


So I did some more testing, and either I do not understand how it is supposed to be measured, or this ET5410 is not what you want when you value dynamic testing.
I mean, it works well for what I bought if for, and the price is right. So I should probably not let this get to me. But the dynamic testing seems to be lacking.


Dynamic CC Continuous:
- Basically works (if we ignore specs)
- Settable resolution is fixed 5-digit ms, so 1ms to 60.000ms. Not in μs like the spec say. And certainly not 50μs to 3600s
- Best rise time I got is about 1A/ms in part of the slope, and 0.3A/ms in the overall 5Amp rise (see screens 1, 2, 3)
- Then again, I find the advertised 1.5/μs very fast. Are those kind of figures normal?

Dynamic CC Pulse:
- Basically does not work. When I turn on or off, the current turns on or off. I am unable to get a pulse out of this
- Rise time is slightly better though when turning on, about 5A/ms, but with overshoot (see screens 4)

Dynamic CC Trigger:
- I think it works. The manual trigger swaps between level A and level B, and thus the  durations have no meaning
- Trigger can be "Auto, Manual, External"  which hints that the cut-off ribbon cable near the back has a trigger in it.
- Rise time is same as Continuous.


Thinking about this, one thought I had is that the rise time is slow, because it is limited.
Maybe there is a settable 1A/ms default somewhere. But if so, I cannot find it.

Another thought is, this is rebrand with (bad) custom firmware. The fixed 5-digit milli-second duration setting, instead of 50μs to 3600s hints at this.
So maybe this is a re-branded OEM and East Tester only makes front panel and new firmware, and they messed up on the firmware but publish the original device's specs.
After all, between the Kunkin, East tester, DingChen, too many nearly similar form factor devices hit the market at the same time.


Images
Sorry for the photos, could not find a FAT formatted USB stick.
Yellow = measured with current clamp probe; Blue = measured with 0.1Ohm shunt


Next up I will redo my IGBT testing, see if my memories on the 20KHz were correct.
But the wheater is good outside, so not now....

[Hydron]

Thanks a lot for the measurements. I would also not use the dynamic mode very often (probably occasionally for testing power supply transient response), but it seemed to be a point of difference between the EastTester and the other similar options. The reviews most people do are based around CC, CV and battery testing rather than looking much at dynamic performance.

As the specs are just lies anyway I'll probably buy based on availability and price instead, or pay the extra for a KEL103 (which has sense inputs built in, a front panel switch unlike the Kunkin, and an ethernet connection). Still good to have options suitable for most hobbyists available for reasonable prices though, unlike a few years ago when Itech was the "cheap" brand.

As for screen capture, there are some python scripts etc available to grab shots via ethernet if that helps you (photos also work though).

[cybermaus]

One feature I do like a lot. And I did not know it was a feature until I say on a Kunkin teardown that it could not do it:
You can change the CC/CR, while it is already active. So while drawing 5 amp, you can walk up or down.

I do that a lot. From the Kunkin video I was let to believe you need to stop the load, change the setting, start the load.
That alone would make me chose for this East Tester instead of Kinkin all over again, had I need for another one.

[Hydron]

Agreed, after I heard about that issue with the Kunkin I was never going to buy one regardless of price difference.

Edit: ...and the above is wrong, read it elsewhere too but must have been user error or something! I've just checked a video and the guy is adjusting it live.

[aristarchus]

That is the problem with those that do reviews and do not even know how to operate the device under review.. thus their videos give wrong impressions to viewers.
Got a KP184 and honestly I believe there is nothing to beat its VFM and the more I see other similar loads the more I appreciate it.

[cybermaus]

@aristarchus
Sorry, I am not quite sure how to interpret your remark.

Anyway, I did do the IGBT test again.
So Load is set as a 4 Ohm resistor, and a MOSFET is drawing current through it, driven by a 20KHz PWM signal.

And indeed, it is doing pretty well emulating this resistor. Maybe it is because it does not need to react, just stable keep its internals set to the emulated 4 ohm, regardless of the PWM state.
But initially when I tested this, I wondered this sort of setup would work, and it does. Even at 20KHz it shows a fairly square amp use.
Note how the amp does jump from 0Ampt to almost 3 Amp (12V over 4 Ohm) but the load display calculates the average current

Yellow is current drawn. (almost 3 Amp peak))
Blue is voltage over MOSFET, connected to Load Negative (12V then open).

[Hydron]

That is the problem with those that do reviews and do not even know how to operate the device under review.. thus their videos give wrong impressions to viewers.
Got a KP184 and honestly I believe there is nothing to beat its VFM and the more I see other similar loads the more I appreciate it.

I assume you mean value for money by VFM?
And yes, it does appear that you can adjust it live, I read somewhere else on the forums (can't remember where) that there were issues adjusting it live but I found a video disproving that - apologies.
If the Kunkin was the only <$250 load then I would get one for sure, however it looks like there are others that are more user friendly and I'm happy to pay a bit more for a nicer UI and a power switch on the front rather than on the back next to LIVE screw heads (i.e. safety modifications required before use).

[cybermaus]

.. next to LIVE screw heads (i.e. safety modifications required before use).

Well, I did check that, not a problem on the East Tester, and also the heatsink is further away from the back plate so you have to go really go in there to even touch the heatsink with a DMM probe.
There are some internal screws at the side of the heatsink though, that potentially touch the sides if they dent. So I did put some felt pads on those.

[Wintel]

Anyway, I did do the IGBT test again.
So Load is set as a 4 Ohm resistor, and a MOSFET is drawing current through it, driven by a 20KHz PWM signal.

And indeed, it is doing pretty well emulating this resistor. Maybe it is because it does not need to react, just stable keep its internals set to the emulated 4 ohm, regardless of the PWM state.
But initially when I tested this, I wondered this sort of setup would work, and it does. Even at 20KHz it shows a fairly square amp use.
Note how the amp does jump from 0Ampt to almost 3 Amp (12V over 4 Ohm) but the load display calculates the average current

Yellow is current drawn. (almost 3 Amp peak))
Blue is voltage over MOSFET, connected to Load Negative (12V then open).

cybermaus, have you try to test the Battery Discharge feature and set to CR "Constant Resistance", ie. connect a battery and set the Battery Discharge feature CR to 5 Ohm or 10 Ohm,  Does it work ?

Because many users report that Battery Test doesn't work with CR, when selected constant resistance nothing happened, only when constant current was selected did it start to discharge.

[cybermaus]

cybermaus, have you try to test the Battery Discharge feature and set to CR "Constant Resistance", ie. connect a battery and set the Battery Discharge feature CR to 5 Ohm or 10 Ohm,  Does it work ?

Because many users report that Battery Test doesn't work with CR, when selected constant resistance nothing happened, only when constant current was selected did it start to discharge.

I checked, and indeed, I am not able to get the CR submode of the Battery test to work. CC works OK, but CR does not.
I tried several cutoff voltages and resistance values, but it just is stuck to about 7~8mA. And no, this was not the value still set for the unused CC mode, those were set way higher.

So it seems this really is a failure of the device.

[Wintel]

cybermaus, have you try to test the Battery Discharge feature and set to CR "Constant Resistance", ie. connect a battery and set the Battery Discharge feature CR to 5 Ohm or 10 Ohm,  Does it work ?

Because many users report that Battery Test doesn't work with CR, when selected constant resistance nothing happened, only when constant current was selected did it start to discharge.

I checked, and indeed, I am not able to get the CR submode of the Battery test to work. CC works OK, but CR does not.
I tried several cutoff voltages and resistance values, but it just is stuck to about 7~8mA. And no, this was not the value still set for the unused CC mode, those were set way higher.

So it seems this really is a failure of the device.

What is the hardware and firmware version of the ET5410?

[cybermaus]

Purchased January 2020
Software: V1.0.1942.024
Hardware: V1.10.1946.002
 

[Wintel]

Purchased January 2020
Software: V1.0.1942.024
Hardware: V1.10.1946.002

Maybe there is a bug of firmware, or will be fixed after firmware update (maybe?!)

Is there any new firmware for ET5410?

[Hydron]

I eventually ended up buying a DCL6104A (rather similar to the ET5411), partly to the info given here - my thanks to the other posters.

It may be of interest that I managed to mod that load for remote sense in a very clean manner - the firmware and PCB supported it already, all that had to be done was add a relay and connector. Details are to be found here: https://www.eevblog.com/forum/testgear/et5410-or-dcl6104-or-a-third-programmable-electronic-dc-load-in-the-budget-cat/
Behaviour with the sense mod is similar to the OP's ET5410, but it can be switched from the front panel or via SCPI. No need for protection of heatsink screw on it either - they are nylon.

Is far from a perfect device (along with the other cheap options), but the price was certainly right and it looks like it will meet my needs for something that can do >150V. Note that very low (mA level) currents are a bit inaccurate (especially before my mods), transient/dynamic mode is only half-working (similar or possibly better than the ET5410), and that the minimum CV voltage is a bit high (~1.35V in my case). A quick test suggested that CR/CP battery modes _do_ work with this load, and I also did a CC test of a NiMH cell with a 0.8V cut-off voltage - worked as expected.

[Algasman]

I just found this thread, also bought an ET5410 last year, opened it and came to the same conclusion to modify it to enable external sense capability. I even took some pics because I wanted to post instructions for the mod but but forgot about it and  unfortunately never did. As soon as I find the time, I will post them here with some comments - stay tuned

[cybermaus]

Hi

When last year did you buy, what is your firmware version, and does your battery mode work in CR mode?

Thanks

[Algasman]

I ordered it from Banggood in Czechia August 31st and got it September 3rd. Firmware and CR battery mode I have to check, right now the device is stored away because I clean up my hobby room / basement.
But I have  the warranty card at hand, date of manufacture is 5.2020, inspected by 05

[Algasman]

I tried CR in Battery mode and agree that it does not work. when setting to low current and low voltage mode, it does not even show current flow even though it draws current.
On the attached picture you can check H/W and S/W revision #

[cybermaus]

Thaks.
So it is slightly newer then mine. But at it still does not work on battery test, I guess it is not so important.

Tbh, I never run into the problem. The device works well enough for me.  A more common slight annoyance I have is that the font is rather small, but that is also related to my aging eyes.

[idolclub]

I tried CR in Battery mode and agree that it does not work. when setting to low current and low voltage mode, it does not even show current flow even though it draws current.
On the attached picture you can check H/W and S/W revision # (Attachment Link)

You may try to ask "East Tester" to get a new ET5410 firmware that is newer than v1.02.2030 (Year 2020, week 30) to fix the CR Battery mode issue.

[ass20]

et5410 do not have fw update  function on menu ....
Do anybody have support email of eat tester  company?

[idolclub]

et5410 do not have fw update  function on menu ....
Do anybody have support email of eat tester  company?

https://www.easttester-cn.com/et54-series-programmable-electronic-load-product/

https://www.easttester-cn.com/contact/

[PaWill68]

Don't even rely on technical support. Forget about her.

[Algasman]

I found the pictures from my mod. They were still on my camera.
Trying to get the pics inline does not work (maybe its a Safari iPad issue). The first three pictures are taken before the modification and show the controller board attached to the front panel and the original wireing. One can see the power lines and the thin black & white sense lines

[Algasman]

Right above the relay is the connector for the sense signals. I ordered some decent Hirschmann Terminals. The big ones are 63A rated.

[Algasman]

Now to the mod: It’s quite easy, since the front panel is the same for the two channel version. So the positions for the sense terminals are defined. Just some drilling and filing necessary.

[Algasman]

The new sense wires soldering and mounted to terminals. All terminals mounted. The main lines are unaltered, just the old sense wires are cut.
The modification is really simple. I did not use a switch, just have to put a bracket between the terminals if I use it without external sensing

[cybermaus]

The new sense wires soldering and mounted to terminals. All terminals mounted. The main lines are unaltered, just the old sense wires are cut.
The modification is really simple. I did not use a switch, just have to put a bracket between the terminals if I use it without external sensing

Brackets may be as good as my switch. I hope the switch will not have contact corrosion in a few years.

More importantly, you did also not think to add polarity protection"

Alas no reverse polarity protection on the now separate sense wires, I am now wondering if I should have shorted the middle of the 4 100K resistors with a diode. After all, the TL072 can only stand -0.3V

I think a diode, with it's 0.6V threshold placed strategically in the middle of that 4x 100K network, would not at all affect precision, but if I accidentally cross the sense wires, it would deflect the negative voltage before it reaches the TL072.

But I did not take any action on it yet.

[Dwaine]

Has anyone seen the newer version with sense wires in the wild?  It's listed on their site, but I have not seen it sold any where yet.

Dwaine

[end0101]

The new sense wires soldering and mounted to terminals. All terminals mounted. The main lines are unaltered, just the old sense wires are cut.
The modification is really simple. I did not use a switch, just have to put a bracket between the terminals if I use it without external sensing

Brackets may be as good as my switch. I hope the switch will not have contact corrosion in a few years.

More importantly, you did also not think to add polarity protection"

Alas no reverse polarity protection on the now separate sense wires, I am now wondering if I should have shorted the middle of the 4 100K resistors with a diode. After all, the TL072 can only stand -0.3V

I think a diode, with it's 0.6V threshold placed strategically in the middle of that 4x 100K network, would not at all affect precision, but if I accidentally cross the sense wires, it would deflect the negative voltage before it reaches the TL072.

But I did not take any action on it yet.

Do you have any alt part suggestions for a 2n4148? Just got one of these (et5410) and planning to do the same type of mods but not finding 2n4148's other than a single ebay listing or any proper datasheets on it other than it suggests it's a thyristor in to52 from 42years ago

[cybermaus]

2N4148? Or did you mean 1N4148?

Well it is hard to remember exactly my plans, and I do not have the schematic.

But for the purpose as I remember it, placed as bridge from the middle of the bottom (GND) pair of 100K resistors, to the middle of the top (+V up to 150V) pair of 100K resistors, it does not need much in way of specs. The front resistors would pick up most voltage as well as reduce current down to a few volts and mA

It  just needs to prevent incorrect polarity from reaching the OpAmp. I think even speed is not to critical, as the OpAmp can probably handle a few useconds.

So pretty much any diode will do, 1N4148, 1N4001 up to 1N4007.

But do check precision before and after.

[end0101]

2N4148? Or did you mean 1N4148?

Well it is hard to remember exactly my plans, and I do not have the schematic.

But for the purpose as I remember it, placed as bridge from the middle of the bottom (GND) pair of 100K resistors, to the middle of the top (+V up to 150V) pair of 100K resistors, it does not need much in way of specs. The front resistors would pick up most voltage as well as reduce current down to a few volts and mA

It  just needs to prevent incorrect polarity from reaching the OpAmp. I think even speed is not to critical, as the OpAmp can probably handle a few useconds.

So pretty much any diode will do, 1N4148, 1N4001 up to 1N4007.

But do check precision before and after.

Gotcha, asked on 2n4148 because it's what you said way back in page 1 :p
So setting up like a voltage isolation transformer (to step voltage down into the range a ideal diode controller can work with) or a voltage transducer (like a v500-iso from Tifomy) and separate power feed to a ideal diode circuit/power mosfet setup wouldn't be necessary in this setup then, I also don't have a schematic.

[cybermaus]

Gotcha, asked on 2n4148 because it's what you said way back in page 1 :p

Oopsie. slip of the keyboard, will fix. I definitely meant a highly generic one, like 1N4148 or 1N4001

So setting up like a voltage isolation transformer (to step voltage down into the range a ideal diode controller can work with) or a voltage transducer (like a v500-iso from Tifomy) and separate power feed to a ideal diode circuit/power mosfet setup wouldn't be necessary in this setup then, I also don't have a schematic.

I have no idea what you mean by this.
Voltage transformer? I just suggest to clamp the voltage if you accidentally reverse connect the sense pair.
Don't want to blow out the OpAmp. But it may not even be needed.

You know what, I am going to open it up and recheck what I meant all those months back.

[cybermaus]

Ok, I opened it and added the diode(s) as in the picture
It will clamp reverse polarity to 0.6~1.0V depending on the input. (I tried up to -20V)
(images 1 & 2)

Also, I added 2x 1n4148, because the small leakage of the diode would affect precision a tiny bit.
And according to the 1n4148 datasheet while up to 5uA max, from the graph you see it is more between 10~100nA, dropping really fast if you stay away from the 75V max rating.
(images 3 & 4)

So by putting 2 diodes serial, we stay nicely away from that.
Not that anyone who buys this C brand would ever truly need that precision.

[end0101]

looks good, I was going over the unit that delivered couple days ago (mine was made jan 2021 and looks like they omitted ps2 port), and some of my igbt legs and copper bars have some of the worst joints/pin not being seated, or outright they skipped out on soldering entirely, may wanna check the joints at top and bottom on copper and igbt legs

edit: think a 1N3595 low leakage from On Semi (digikey has 1N3595TR on cuttape for 0.24 us cents ea or 10 for 2usd) would be the ideal diode? low forward @10ma (0.65-0.8 ), 150v peak, 1na @125v reverse leakage, not really doing high speed switching to need the 4ns unless I am forgetting something?

[cybermaus]

I think a 1N3595 low leakage from On Semi (digikey has 1N3595TR on cuttape for 0.24 us cents ea or 10 for 2usd) would be the ideal diode? low forward @10ma (0.65-0.8 ), 150v peak, 1na @125v reverse leakage, not really doing high speed switching to need the 4ns unless I am forgetting something?

With 1nA 150V it would surely seems like a better option.
And I see no other problems with its specs, other then the fact you would need to special order them.

But still I think the 1N4148 is quite good enough for this purpose, especially as you (presumably, like everyone else) already have those lying around.
So it is all your own choice.

And before you value my ideas about all of this: I am only a hobbyist, I am not even sure the OpAmp even needs protection.
The TL072G OpAmp specs do list -0.5V absolute max common voltage, but also -10mA (so reverse) input current.
I just got it in my head that now the sense lines are separate, so I could make the mistake of hooking them up wrong, and I guessed the diode does not make it worse (ignoring the tiny leakage current)

BTW: I did hook up the main current inputs wrong once for a handful of seconds, and it shorted out the CC power supply, but both survived.

[gico750]

Hi, I buy from aliex a ET5410, please could you explain to me why you need the modification and bring the thin wires on other bushings? thank you

[gico750]

I mean the sense wires which have been placed centrally with two bushings

[cybermaus]

@gico750

it is only needed if you want to ignore any voltage drop that your connection leads may give.


Consider the example case: 12V power supply that you want how far the voltage drops between 0-3 Amperes
If your test wires are thin, your test wires themselves may drop .5V Or more

So you measure 11.5V at 3A load, thinking that your power supply is loosing voltage quickly. But the power supply may be keeping up nicely, and it is your wires.
By moving the voltage measure point to the power supply, you eliminate this problem
Look into generic explanations of 4-wire voltage measurement and kelvin clamps.

Alternative and easier solution would be to ensure you always use thick wires, and not cheap china ones.
If you want to measure up to 3Amp, use wires that are rated to 30Amps. Or something like that.

[gico750]

thanks for the answer, yesterday the tool arrived and I would like to make this modification, so just detach the thin wires and put them thicker in the center of the panel with two bushings, but then how are they used?
Sorry but I'm not very experienced.

[gico750]

ok, i read the 4 terminal measurement and saw the kelvin tweezers ....
Now he wants to understand only the diodes you put to protect the opamp.
Are they just those two I see in the picture? Thank you

[cybermaus]

just detach the thin wires and put them thicker in the center of the panel with two bushings

They do not even need to be thicker. The sense wires can be thin.

ok, i read the 4 terminal measurement and saw the kelvin tweezers ....
Now he wants to understand only the diodes you put to protect the opamp.
Are they just those two I see in the picture? Thank you

Yes, only those two diodes in the picture. I am not even absolutely sure it is needed, but I feel it is safer.

[ceut]

Hello !
I have made a small mod for the (too loud) fan.
I use a lot 40°C Thermal Switch (Normally Open) for many devices which have too loud fan (I don't know the real name of this component).

So the Fan is completely shutted down when the temperature is under 40°C   

The mod is simple, only take time to find how to put the sensor...
Here are somes photos 
Also, you will see a "Fan Error" icon on the top of the screen, which disappears when the Thermal switch is on: it is a good feature 

I have checked with my lab powersupply at 20V/3A: no problem it works well 
(Siglent SPD3303)

Edit: I think I will buy a Noctua 80mm fan (or something like this) to replace it, too loud for me when it is active.

Edit2: Here is the no-name fan reference, 12V/0.35A/ 4500rpm

[cybermaus]

I have made a small mod for the (too loud) fan.
I use a lot 40°C Thermal Switch (Normally Open) for many devices which have too loud fan (I don't know the real name of this component).

Hmm, that is not a bad idea. Simple enough.
It's just called a thermostat. Probably this model uses a simple bi-metal switch.
Next time I order some stuff I should have some come along.

Can I suggest to you that you put some sort of isolation on the scews for the heat-sinc stands?
They are connected to the Red (+) terminal. One small dent in the side, and you are shorting the latter to ground.
I just put some felt pads between the screws and the sides. It not only isolates, but also helps prevent dents and reduce vibrations.

[ceut]

I have made a small mod for the (too loud) fan.
I use a lot 40°C Thermal Switch (Normally Open) for many devices which have too loud fan (I don't know the real name of this component).

Hmm, that is not a bad idea. Simple enough.
It's just called a thermostat. Probably this model uses a simple bi-metal switch.
Next time I order some stuff I should have some come along.

Can I suggest to you that you put some sort of isolation on the scews for the heat-sinc stands?
They are connected to the Red (+) terminal. One small dent in the side, and you are shorting the latter to ground.
I just put some felt pads between the screws and the sides. It not only isolates, but also helps prevent dents and reduce vibrations.

Hello,
Thank you for your great advice !
I have teardowned again my ET5410 because I have received an Arctic F8 fan (airflow=31CFM), to try it inside.

And you are totally right ! The (+) is on the heatsink 
In fact, it is because there are no thermal isolation pad between the mosfet tabs and the heatsink (maybe the heatsink is a part of the current sinking :-? )
So I have put 2 pieces of ductape on each of the 2 opposites screws.

For the F8 Fan: it is a failure  the airflow is too low 

I have checked all good PC fan brands (Noctua, Arctic, Coolermaster, Antec, bequiet and other brand) and I can't find any that matches the one inside (I have looked for a 0.35A / 4.2W fan at 4000rpm).
I have ordered a little UT363 to check the airflow, but I'm stuck.

Mine has an horrible metallic noise when it's rotating: I think there is a bad ballbearing inside.
Fortunately the "thermostat" saves me    (it is a simple bi-metal switch as you say=>there is a very little "clic" like a relay when it is activating)

If someone has an idea to replace the 80mm fan inside ?


Edit: I have ordered a Arctic "P8" version: it is the high static pressure version, to try it...

[vav]

Hi, I'm the new owner and I made some adjustments. I placed the
1.USB port on the front panel
2. I added terminals for 4W measurement
3. I added a 2W / 4W switch
English is not my native language, I use a translator.

[cybermaus]

Hi, I'm the new owner and I made some adjustments. I placed the
1.USB port on the front panel
2. I added terminals for 4W measurement
3. I added a 2W / 4W switch
English is not my native language, I use a translator.

looks nice.

[T3TRIS]

Well, I'm reviving this one, hopefully!
I bought an East Tester ET5410A+ DC load and have been using it for testing LiFePO4 battery builds. It has worked fine so far and has been useful for capacity tests. However, one of these capacity tests is pointing to an issue with battery I made, and I now want to test individual cells. The issue that brings me here is the voltage sense wires. They aren't critical for an assembled battery with BMS but for single cell tests, it's a pain. I had started a 40A load test on one cell, telling the load to stop at 2.5V. However I quickly noticed the 0.5V voltage drop between the cell terminal and the load (using 6AWG cables and crimped lugs).
Anyhow, I now want to do this voltage sense wire mod, but apparently the A+ version of the ET5410 doesn't look friendly to that!

I can solder some wires to banana plugs, but to be honest, finding where to solder on this board seems to be above my pay grade.

Has anyone ever figured this one out?

I also sent an email to East Tester directly to see if they can assist.

Thanks

[Hotcooler]

Has anyone ever figured this one out?

I also sent an email to East Tester directly to see if they can assist.

Did you get any reply? In theory there is a compenstation function that seem to work on videos, have you tried it?

[T3TRIS]

Oh I have not!! I didn’t know this was a thing (didn’t see a video). What I’ve done so far is use oversized wires and decrease the amperage toward the end of the test, which reduces the voltage drop. I’ll have to find that video, thanks!

[Hotcooler]

Oh I have not!! I didn’t know this was a thing (didn’t see a video). What I’ve done so far is use oversized wires and decrease the amperage toward the end of the test, which reduces the voltage drop. I’ll have to find that video, thanks!

Here you go : https://youtu.be/pT5kuc2fNRQ?t=1778

I have one on order, since it was.. very attractively priced compared to the older version or even the DL24E in a resonable setup, so yet to test that myself.

[T3TRIS]

Here you go : https://youtu.be/pT5kuc2fNRQ?t=1778

I have one on order, since it was.. very attractively priced compared to the older version or even the DL24E in a resonable setup, so yet to test that myself.

So simple! Thank you for sharing. I’ll test it when I get back home.

[kawal]

Post some more pictures of the board with focus on the area close to the metal bars.  Shine a light behind the board to  see the traces. Most likely the voltage measurement is in the area of the op amps close to the metal bars.  There are probably some tiny traces going away from the bars area to measure voltage. 

[kawal]

Anyone want to do the remote on ET5410+ this is how:

Cut traces going to the terminal
Solder wires to resistor pads as shown . Other side will be your sense connections.

[mawyatt]

If these are cut/opened don't you run the risk of having unknown voltage sensing without the sense cables connected?

Would think a safer approach would be to add some series R of equal value, maybe 1K, in each leg where you would have the opens, then wire the sense terminals as you've shown. If the sense cables aren't attached or fall off you still have voltage feedback, and if the sense cables are utilized they short out the 1K added resistors to compensate for the load current carrying cables.

Anyway, just some thoughts.

Best,

[andyB2022]

How I would do it, First cut the traces mentioned by kawal, now we have an open middle point (the place we cut) from the lef of the cut run 2 wires to the middle conection of a DPDT switch, then from one of the switch positons run wires back to the side going to the resistors (right of the cut) and another pair of wires (using the last contacts on the switch) towards an external connector. I would do it with a BNC.

Cost-effective and reliable.

Here is how my ET5410 looks:

[cybermaus]

Those new A+ versions of the EastTester. What firmware version is it, and did anyone manage to get to the FLASH and download it?

[andyB2022]

Those new A+ versions of the EastTester. What firmware version is it, and did anyone manage to get to the FLASH and download it?

Did you manage to get the flash?

[cybermaus]

No, and also looking at the buttons a bit better, it's clearly different hardware, so the firmware would not work.
Still, what is, and who has, the latest firmware for the old model.

The latest mentioned here is  v1.02.2030 (year 20, week 30), but I do not even have that, I have V1.0.1942 (year 19, week 42)

[DaneLaw]

Got one of the old ones' just in the final weeks before the new (A) was the norm, but it was from Banggood from their EU store, when they cleared EU stock at attractive prices, so the unit I got' could have been in storage for some time.. - it arrived with this FW&SW.  (8 pictures down)  https://tinyurl.com/4ujvpybv

But its usually bag'ed for mobility, in lack of a dedicated lab bench.. https://tinyurl.com/yc64xbmp

[andyB2022]

Got one of the old ones' just in the final weeks before the new (A) was the norm, but it was from Banggood from their EU store, when they cleared EU stock at attractive prices, so the unit I got' could have been in storage for some time.. - it arrived with this FW&SW.  (8 pictures down)  https://tinyurl.com/4ujvpybv

But its usually bag'ed for mobility, in lack of a dedicated lab bench.. https://tinyurl.com/yc64xbmp

Is there any way you could try to dump the firmware off the STM32? I need it for my unit...

[DaneLaw]

Hi Andy, I saw your comment about your issue, but extracting the fw of the STM32 is sadly not something I can help you with.
Have you tried to contact East Tester?

This seems to be their sales email.
sales1@east-tester.com
Phone
+86-13396517215
+86-571-56770221

[andyB2022]

Yeah, no response so far.

[DaneLaw]

Yeah, no response so far.

If you do not hear back through email, then try the telephone (it's quite cheap these phonecalls to CN nowadays) and have your details ready, like serial number  etc, and emphasize that the phone support starts a case on your behalf, and ask for that case/journal-number, so you have something tangible to build on, if you have to call back, as otherwise, you can risk they just sing you a tune, on how they "love you long time, & will get back to you" and never do, and you have to start over and explain it all again to the next phone support worker.

[andobovsayvkub]

Hello. I just made a connection for 4 wires on 5410A+. I cut the traces and simply added a 22 ohm resistor between +V and +SENSE. Setting more then 20 Ohm will lead to an measurement error with 2-wires, and low values will cause voltage drop with 4-wires.
This made it possible to use both a 2-wire connection and a 4-wire connection without adding a switch. The standard behavior of the device has not changed.
Yes, it is possible that a voltage error may occur with a 2-wire connection but no more than 1 in the last digit on the screen. Tested in the range of 5-60V, 0-25A. And it still measures absolutely accurately with 4-wires connection. Also thinking of diode protection, but later.

part of original


new one


appearance


And one more moment. The motherboards have been replaced due to a transistor that burned out on the first day. And I can't remember if the "software sense" function worked correctly when measuring the resistance of the wires connected to the battery or to other weak source.
The line resistance measurements are correct with a laboratory power supply. But when I try to measure the line resistance with the battery connected, I get incorrect data as the source voltage has a drawdown. Is it like this for everyone or is the new board also defective?
That was my the main reason to transfer it to 4-wires schema.