Using a uCurrent with Siglent SDS1204X-E or SDS1000X-E series (feature request?)

[tautech]

@Performa1: Why the scope vendors (ie your friends at Siglent) do not publish a "beta versions" of their firmware? Why to wait 6 months for a release??
The best testers are the users it seems
Even large motherboard's vendors do it..

This is the release version:
http://www.siglent.com/ENs/gjjrj-xq.aspx?id=2323&tid=15

We got an earlier beta version and I strongly suspect there were versions before that.
Where do you get 6 months ? 
They were only released in late Nov 17.

[Performa01]

@Performa1: Why the scope vendors (ie your friends at Siglent) do not publish a "beta versions" of their firmware? Why to wait 6 months for a release??
The best testers are the users it seems
Even large motherboard's vendors do it..

Sorry if I have been unclear.

My "friends at Siglent" are the relevant persons in product management and R&D that I'm pushing really hard to make these entry level scopes as good and flawless as possible - to the benefit of all current and future users out there. That's the one and only purpose why I have this scope and provide extensive reviews.

Beta testers receive non-public versions of the firmware prior to the release of a new product or a new major feature for an existing product - but even they don't get quick hacks within a couple of days after a feature request.

Regular firmware updates are about every 6 months and it might be a bit more frequent in the introduction phase.

In this particular case I have asked whether it's possible to provide a quick intermediate firmware release very soon as there is member cardre who needs a certain feature right now. Mind you, we're not talking about a bug fix, just additional support for a third party (kind of) probe. Siglent takes this seriously and have agreed to make a new release available as soon as possible. Getting a new feature within a couple weeks after the initial request is not too shabby in my book.

[Performa01]

For your example of the uCurrent however, if it actually outputs 1mV/nA (which would be equivalent to 1V/uA = 1MV/A), then you need a probe multiplication factor of 0.000001 = 1E-6. This would be at the edge of the range that I’ve suggested (1E-6 to 1E6).

Thanks Performa01, I realised that I had used the wrong units (nA) instead of (uA) in my example, so I've corrected this above in my post.

You're spot on, of course, and it would need a 1E-6 for the nA mode of the uCurrent. If Siglent can provide down to that level and keep the units correct, this will help with those even lower current measurements down at that scale. I'm still (just) in the uA range with my current project, so I should be happy with even just 1E-3, but who knows in the future!

The 1E-6 to 1E6 range for custom probe multiplication factors is what I've proposed to Siglent and from their reply I have no reason to believe we won't get that - maybe even more, who knows...

When looking at measurements and math, we can see all sorts of unit prefixes, at least down to pico, but I think I've even seen femto at times. So I'm positive we'll see anything from (at least) pA up to (at least) MA whenever measurement or math results call for that.

[Performa01]

I did some tests with the current 7.6.1.20R1 firmware just to make sure prefixes and units are handled correctly. I could see prefixes ranging from pico to mega as expected, which should cover all practical use cases for this DSO. I did not see femto though, so this must have been on some other scope.

First I tried simulating high currents by using 100V DC with a 10k probe factor.


SDS1104X-E_Int_DC_MA

Channel settings are displayed in kA, while math, automatic and cursor measurements use MA as required.


With the 0.1x probe factor, the lowest setting can be 50uA/div, but standard deviation in the measurement statistics is in nA and on a fast timebase, the integral can be brought down to the pAs range.


SDS1104X-E_Int_Pulse_uA

After these tests, I am positive that units and prefixes shouldn’t be an issue with the custom probe factors – but we’d need the femto prefix, see below...

I’ve also spotted a potential improvement for math functons in general and the integral in particular: the range for the Scale parameter could be a little wider than it is now.

The 2nd example uses the maximum sensitivity, which is 500pAs/div for 0.1x probe factor. Even though this should just be enough for real world applications, I would still think that it wouldn’t hurt to be able to go down to 100pAs/div (equivalent to 1nAs/div for 1x probe factor).

For the new probe factors down to 1E-6, we have to go much lower and would need the femto prefix indeed:

Probe Factor   min. Scale
1E+6               1 mA/div
1E+5               100 uA/div
1E+4               10 uA/div
1E+3               1 uA/div
1E+2               100 nA/div
1E+1               10 nA/div
1E0                 1 nA/div
1E-1                100 pA/div
1E-2                10 pA/div
1E-3                1 pA/div
1E-4                100 fA/div
1E-5                10 fA/div
1E-6                1 fA/div

There is also an issue in the first example, where I’ve used the highest Scale of 200kAs/div and this is not enough to get the entire math trace on the screen. I’m not entirely sure how the maximum Scale is determined, yet generally it appears to work just fine - just not in that particular case, where maybe some hard upper limit comes into effect.

In order to demonstrate that the upper Scale range is usually wide enough, I’ve tried the most extreme situation by setting a -2A offset in the 500uA/div range (1x probe factor). The integral can be scaled to fit the screen just fine:
 

SDS1104X-E_Int_DC_Offset_1ms

I have also tried a 1s/div timebase setting, and the math Scale automatically changed to 5As/div, just as it should be.

[iMo]

Does the scaling work with FFT result too?

[Performa01]

Does the scaling work with FFT result too?

If you mean the probe multiplication factors, they affect the FFT level results indeed.

Here are two examples for 1x and 10x probe factors:


SDS1104X-E_FFT_1x_-13.86dBV


SDS1104X-E_FFT_10x_6.14dBV

The difference of the two measurements is 20dB, just as it should be.

[cardre]

In this particular case I have asked whether it's possible to provide a quick intermediate firmware release very soon as there is member cardre who needs a certain feature right now. Mind you, we're not talking about a bug fix, just additional support for a third party (kind of) probe. Siglent takes this seriously and have agreed to make a new release available as soon as possible. Getting a new feature within a couple weeks after the initial request is not too shabby in my book.

Wondering if there's any further update on when the new probe factors firmware update being released?

Thanks.

[Performa01]

In this particular case I have asked whether it's possible to provide a quick intermediate firmware release very soon as there is member cardre who needs a certain feature right now. Mind you, we're not talking about a bug fix, just additional support for a third party (kind of) probe. Siglent takes this seriously and have agreed to make a new release available as soon as possible. Getting a new feature within a couple weeks after the initial request is not too shabby in my book.

Wondering if there's any further update on when the new probe factors firmware update being released?

Thanks.

Not sure if I understand this question correctly...

This is an intermediate update and it certainly will not be the last one.

If you mean whether this update includes more improvements and fixes than just the custom probe settings, then this is a "yes" as well.
We know at least that some issues with the serial decoders have been addressed, one of these has even been discussed briefly in this thread.

Several other issues should have been addressed as well, the majority of them not detected/reported by anyone else but me, so Siglent might decide to not include (all of) them in the public changelog.

I do not know by now what exactly the new release includes.

Btw, as you have noticed, the new firmware is delayed - probably due to the fact that I've requested that the fixes for the probe menu and the I2C decoder meet certain criteria and all this might have introduced additional effort that hasn't been anticipated right from the start.

Anyway, we can expect the release within the next couple of days. I got a notification that it is in the final production testing right now.

[cardre]

In another thread its been mentioned a new 1204X-E scope was just purchased with a .20 R2 firmware version. I can't find this new version to download anywhere yet. Does anyone know how to get this updated release?
Thanks.

[Performa01]

You'll not get a 7.6.1.20R2 firmware.

It would not be the first time that new units had a firmware with just one minor change compared to the (then) current official release.

The coming release will be much more than just the minor step from a R1 to R2. For instance, apart from the things we already know, like the custom probe factors and the fixes/improvements for the serial decoders, it will include an improved web server, several new SCPI commands and the hardware implementation of the X/Y mode (to speed it up significantly - as I've announced in my review back then).

[Performa01]

Finally the new firmware has passed the production test at Siglent and is ready to be released. It contains quite a bit more changes than the fixes discussed in this thread. See the following posting for more details:

https://www.eevblog.com/forum/testgear/siglent-sds1104x-e-in-depth-review/msg1555936/#msg1555936