Author Topic: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes  (Read 174264 times)

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Offline n3mmr

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1250 on: March 01, 2019, 12:51:01 pm »
What i was after was a command that would put it in a bode plot mode with the parameters exposed so I could set the center, span, etc via scpi,
Officially; Bode plot SCPI command set: totally unsupported at this time.

Rerouter would like it, please raise hands who else.

 :-+
 

Offline mroek

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1251 on: March 01, 2019, 01:12:03 pm »
@rf-loop: Thanks for taking the time to write down that explanation. As I wrote, I thought it was just a visual effect, and you explained why.

I have yet another question on the offset issue. On my scope, the offset is different for each coupling type (DC/AC or GND). Ideally, the offset should be zero for any coupling (when there is no input signal), and even if it may not be a real problem, it would have felt better to see that the offsets was zero. Some channels are "better" than others, though.

I guess there are many owners of this scope that reads this thread, and I am curious if this is normal for this model.
 

Offline tinhead

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1252 on: March 01, 2019, 01:52:40 pm »
I am curious if this is normal for this model.

actually it might depend on model, hw revision, etc., i do have same hw as yours, so let me check later what results are on my SDS

EDIT: yep, that seems to be model specific thing, tested with various settings (but always inputs set to 20MHz and GND, x1, hw1.4), i can get always on some channel 0V and on other some uV offset, worst case was 199uV for CH3 at 1mv/DIV. The good news, with increasing DIV/sec (from 20mv/DIV) it remains low in compare to DIV setting (e.g. 550uV for CH3 at 100mV), 0->0,25%->0,5% of DIV/sec setting, so can be ignored. For the 500uV it is on my SDS better as with 1mV/DIV, 2mv/DIV and 5mv/DIV are "equally bad" on some channels and differs on others (e.g. 200uV at 2mV/DIV, and 200uV at 5mV/DIV).

For DC/AC offsets, they of course depends on environment noise, coupling, DIV setting, so it does not matter to compare anything.
« Last Edit: March 02, 2019, 07:46:03 pm by tinhead »
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Offline mroek

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1253 on: March 06, 2019, 04:07:48 pm »
@tinhead: Thanks for confirming this. I guess it's normal with these scopes, then. I was also able to get the self calibration a bit better on mine, by wrapping some aluminium foil over the inputs to shield them from EMI. After discovering this, I also created some 3D-printed BNC caps which has a spring loaded plate (with aluminium foil on it), that closes the opening of the BNC.

Other than that, today my scope crashed. The UI became unresponsive, but the trace was still "alive". I could connect to the internal web server in the scope, and I could spin up a telnet daemon to connect to it as well. From there I rebooted it, and it came back up as normal. I didn't try the power button while it was in this state, so I don't know if that would have responded.

Having it crash isn't very confidence inspiring, and it was obviously the scope app itself that crashed, as the kernel was still running. It was a bit sluggish, though. The web server loaded very slowly, and the telnet command line was also pretty slow. Unfortunately I didn't look at the CPU usage before rebooting, so I can't say which process(es) was eating CPU time.

If this happens again, is there something useful to be saved out and sent to Siglent for debug? I didn't think to preserve the system logs either, unfortunately.

I also found something about the FFT that I don't really understand, so I'll try to recreate that situation and ask if it's just me, or if it's actually not expected behaviour.
 

Offline Rerouter

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1254 on: March 06, 2019, 08:31:55 pm »
It should not have been the system app that crashed. As the scpi interpriter goes down when the system app locks up.

Cant say exactly what happened. But i can confirm there are a number of commands that can cause a soft lock. Power button for 7 seconds causes a forced shutdown of the psu. And aslong as you have not remounted things to read/write there is no harm in this.

The only way to actually see what the error messages are to my own understanding is to have first closed and then reopened the main application. It will then give debug errors each time something happens.

Other than that. Any clue where you where when it became unresponsive. Personally it almost sounds like the keyboard comms stopped working (has its own micro from memory)
 

Offline mroek

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1255 on: March 06, 2019, 09:05:52 pm »
Ok, if the main app is responsible for the SCPI comms, then I agree that it must have been something else that crashed.
I was doing some FFT analysis when it crashed, and the exact point was when I went to change the memory depth in the acquire menu. I think the scope was in the stop state, and the waveform was possibly zoomed in a bit. The crash happened immediately when I selected a different (smaller, I think) memory depth.

Oh, and the FFT issue I mentioned in my last post was entirely my own fault. I used settings that could not give me the results I was expecting.
 

Offline mroek

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1256 on: March 07, 2019, 12:55:29 pm »
Ok, my scope is back in a bad place... It appears to be in a similar situation as I described earlier, but I'm not sure it is actually a crash. Turns out it does respond to buttons, it's just EXTREMELY sluggish, and it takes several seconds for anything to happen.

I've connected to it by telnet (using SCPI to spin up a telnetd), and here's what top shows:

Code: [Select]
Mem: 107104K used, 129592K free, 0K shrd, 4294967295K buff, 5K cached
CPU:  5.2% usr  1.6% sys  0.0% nic 93.0% idle  0.0% io  0.0% irq  0.1% sirq
Load average: 1.09 1.03 0.67 3/83 14408
  PID  PPID USER     STAT   VSZ %VSZ CPU %CPU COMMAND
  797     1 root     S     370m159.8   1  6.7 /usr/bin/siglent/sds1000b.app
  798     1 root     S    20224  8.5   0  0.0 /usr/bin/siglent/vncserver
14364 11198 root     R     3152  1.3   0  0.0 top
27390     2 root     SW       0  0.0   0  0.0 [kworker/0:1]
  923     2 root     SW       0  0.0   0  0.0 [RTW_CMD_THREAD]
   10     2 root     SW       0  0.0   0  0.0 [migration/0]
  817   811 root     S    13132  5.5   0  0.0 /usr/bin/php-cgi
  811   809 root     S    13048  5.5   0  0.0 /usr/bin/php-cgi
  922     1 root     S     5032  2.1   0  0.0 wpa_supplicant -Dnl80211,wext -iwlan0 -C/usr/bin/siglent/usr/wifi/wpa_supplicant -c/usr/bin/siglent/usr/wifi/wpa.conf
11151     1 root     S     3236  1.3   1  0.0 telnetd -l/bin/sh -p9999
11198 11151 root     S     3152  1.3   0  0.0 /bin/sh
  813     1 root     S     3152  1.3   0  0.0 -/bin/ash
    1     0 root     S     3148  1.3   1  0.0 {linuxrc} init
  809     1 root     S     2668  1.1   0  0.0 /usr/sbin/lighttpd -f /etc/lighttpd.conf
  796     1 1        S     2096  0.8   1  0.0 portmap
 9624     2 root     SW       0  0.0   1  0.0 [kworker/1:1]
    7     2 root     SW       0  0.0   1  0.0 [rcu_preempt]
    3     2 root     SW       0  0.0   0  0.0 [ksoftirqd/0]
   11     2 root     SW       0  0.0   1  0.0 [migration/1]
   12     2 root     SW       0  0.0   1  0.0 [ksoftirqd/1]
  503     2 root     SW       0  0.0   1  0.0 [spi32765]
   17     2 root     SW       0  0.0   1  0.0 [kworker/u4:1]
  652     2 root     SW<      0  0.0   0  0.0 [kworker/0:1H]
  653     2 root     SW<      0  0.0   1  0.0 [kworker/1:1H]
  673     2 root     SW       0  0.0   0  0.0 [ubi_bgt0d]
  684     2 root     SW       0  0.0   1  0.0 [ubi_bgt1d]
    2     0 root     SW       0  0.0   1  0.0 [kthreadd]
    5     2 root     SW<      0  0.0   0  0.0 [kworker/0:0H]
    8     2 root     SW       0  0.0   0  0.0 [rcu_sched]
    9     2 root     SW       0  0.0   0  0.0 [rcu_bh]
   14     2 root     SW<      0  0.0   1  0.0 [kworker/1:0H]
   15     2 root     SW<      0  0.0   1  0.0 [khelper]
   16     2 root     SW       0  0.0   0  0.0 [kdevtmpfs]
   19     2 root     SW<      0  0.0   0  0.0 [perf]
  258     2 root     SW<      0  0.0   0  0.0 [writeback]
  262     2 root     SW<      0  0.0   1  0.0 [crypto]
  263     2 root     SW<      0  0.0   0  0.0 [bioset]
  265     2 root     SW<      0  0.0   1  0.0 [kblockd]
  294     2 root     SW<      0  0.0   0  0.0 [edac-poller]

I can't really see anything standing out, the load appears reasonable, and there's lots of free memory.

Then I checked dmesg, and it's filling up with this error message:

Code: [Select]
[ 6583.202520] DMA timed out
[ 6587.292521] DMA timed out
[ 6591.382523] DMA timed out
[ 6595.482523] DMA timed out
[ 6599.572518] DMA timed out
[ 6603.662519] DMA timed out
[ 6607.752520] DMA timed out
[ 6611.842607] DMA timed out
[ 6615.922520] DMA timed out
[ 6620.012531] DMA timed out

I'll just have to reboot it now, but again I suspect this happened due to me using the FFT feature.

Edit to add:
After rebooting, and checking top again, it turns out that the main scope application should use quite a bit of CPU, it seems to hover around 40% most of the time. So my posted output from top is actually not normal in the sense that the scope app uses less CPU than normal. Probably due to the DMA problem.
« Last Edit: March 07, 2019, 01:04:52 pm by mroek »
 

Offline Rerouter

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1257 on: March 07, 2019, 01:12:57 pm »
So the CPU is almost Idle, but the FFT is throttling, does winding down the settings of the FFT before you start it help or hurt?

(My assumption is FFT is on the FPGA as large memory FFT's are expensive even on an ARM core)

Out of curiosity, could you kill the sds1000b.app and open its file, (not as a separate process), I'm curious if it gives any additional information when it starts hanging.
 

Offline mroek

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1258 on: March 07, 2019, 01:17:49 pm »
I'll try to recreate the situation a bit later, if I can. What do you mean by winding down the FFT settings before starting? Starting what?
And yes, if I can get it back into this situation, I'll try killing the sds1000b.app, and then starting that manually in the foreground. I suppose that's what you meant?
 

Offline mroek

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1259 on: March 08, 2019, 04:52:47 pm »
I've been trying to get it to fail/crash (again) by retracing my steps, but so far I haven't been able to.

However, I found another bug, which I guess no one else has noticed (which is no wonder, since it's rather obscure). I'm using a wifi adapter in mine (the standard TP-Link one), and it's connected to my wifi and working fine. However, I decided I wanted to see if the scope tries to connect outside my network (typically doing the "phone home" dance), so I started a packet trace on my router.

Well, it doesn't try to connect to the outside, but it sends DHCP requests about once a second. That's just dumb, and obviously a bug. It doesn't care about the lease time it gets in the DHCP offer (12 hours in my case), and just continues to spew out the requests. To avoid this, it is necessary to disable DHCP in the scope, and just set a static IP instead. Which I don't really like, even if it's not a big deal.

I haven't checked if the same happens with wired ethernet, though.
 
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Offline tinhead

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1260 on: March 08, 2019, 08:01:19 pm »
... it crashed
... it sends DHCP requests

this might be however related to the beta firmware, i would say install the latest official firmware and check how it works.

EDIT: hint: i did it as well, because in my case SAG1021 was playing crazy with that beta, with the latest official no issues
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Offline mroek

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1261 on: March 08, 2019, 09:02:59 pm »
Yes, I guess I could try going back to the official release. Are there any known issues with downgrading?
 

Offline mroek

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1262 on: March 08, 2019, 10:20:45 pm »
I did the downgrade back to the official version, didn't have any specific issues, except the self calibration that is somewhat worse.

And the DHCP bug (at least for wifi) is still there. As long as it is enabled, it badgers the DHCP server constantly.
 

Offline Max2018

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1263 on: March 10, 2019, 04:47:34 am »
I'll just have to reboot it now, but again I suspect this happened due to me using the FFT feature

Had the same problem once without using the FFT function. In my case the screenshots taken with the print button where all the same regardless on what was actually on the screen.
Since where are here talking about bugs: the trigger channel label updates itself only after switching to a different menu.
 

Offline tautech

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1264 on: March 10, 2019, 09:10:10 am »
Since where are here talking about bugs: the trigger channel label updates itself only after switching to a different menu.
If you please, when reporting any suspected bug, please include the firmware version used.

I've checked my SDS1104X-E with FW version 6.1.26 and I see no indication of any problem with values in the trigger channel labeling.
Please offer better/more info so this issue can be replicated at the factory for correction in future firmware.
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Offline Max2018

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1265 on: March 10, 2019, 09:29:53 am »
@tautech Does not annoy me enough to download new firmware or properly report it. Installed version is the fist one with the file format Version 2.0 released around July/August 2018.
https://www.youtube.com/embed/yWBrk9XO0_E   (Not the best video quality but this due to the blackberry camera.)
 

Offline tautech

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1266 on: March 10, 2019, 09:42:31 am »
@tautech Does not annoy me enough to download new firmware or properly report it. Installed version is the fist one with the file format Version 2.0 released around July/August 2018.
https://www.youtube.com/embed/yWBrk9XO0_E   (Not the best video quality but this due to the blackberry camera.)
Last/current FW was 2018-09-26; V6.1.26

Your video link doesn't work.
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Offline Max2018

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1267 on: March 10, 2019, 10:57:25 am »
fixed the video link: forgot to set the video to public
 

Offline Lazyengineer

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1268 on: April 02, 2019, 03:49:41 pm »
Sorry for bringing up the bandwidth topic up again in this thread. However, based on previous posts in this thread there is still something technical that is bothering me in regards to the mod200.
I measured the BW of the scope before and after the mod200 and get similar results (see graph below).

As you can see, the mod200 BW is way to wide to suppress aliasing. In 2-CH (per ADC) mode (500MB/s sample-rate) the Nyquist is at 250MHz where the input attenuation is only 2dB. In 1-CH (per ADC) mode (1Gb/s) the alias frequency is 500MHz and attenuation only about 17dB.

In original state (no mod) I do not see aliasing problems at 250MHz nor 500Mhz due to attenuation being >>20dB.
The original state (no mod) must have an input hardware LPF. But that seems to get switched off completely in mod200 state. If the original state (no mod) would have been simply a more narrow-band DSP filtering then I would see aliasing during tests, which I don’t.

So, how can one say that the scope can work as a normal 200MHz scope? Shouldn’t a decent scope have an input hardware low-pass filter that suppresses aliases? Does anyone have attenuation measurements of a true SDS1204X-E if that operates the same as mod200?

« Last Edit: April 02, 2019, 03:53:35 pm by Lazyengineer »
 

Online tv84

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1269 on: April 02, 2019, 04:27:55 pm »
So, how can one say that the scope can work as a normal 200MHz scope? Shouldn’t a decent scope have an input hardware low-pass filter that suppresses aliases? Does anyone have attenuation measurements of a true SDS1204X-E if that operates the same as mod200?

I think there have been plenty of comparisons throughout the years.

What you should ask is for a guy with a SDS12000X-E to license it to 100MHz and analyse it's behavior. That would finally clear if the HW (100/200MHz) is the same or not.

 

Offline gamerpaddy

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1270 on: April 02, 2019, 11:54:34 pm »
@mroek
I had this issue aswell, did some logic analyzer stuff and turned it off / plugged out. a month later, plugged it back in and bootup.  buttons respond very delayed, nothing really useable.
reboot didnt fix it but a quick hit on the default button fixed it immediately.
 
 

Offline Lazyengineer

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1271 on: April 07, 2019, 12:29:08 pm »
@tv84: Thanks for the feedback.
Let me add some more context to my question:

rf-loop did some initial frequency response measurements of the SDS1104X-E in Reply# 808
https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg1623214/#msg1623214]http:// [url]https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg1623214/#msg1623214[/url]

Performa01 in Reply# 817 followed up with the measurements for a real SDS1202X-E confirming the similar response compared to a mod200 SDS1104.
https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg1624003/#msg1624003]http:// [url]https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg1624003/#msg1624003[/url]
I am also presuming that the SDS1202X-E has the same front-end as the SDS1204X-E.

In Reply# 829 rf-loop added some great alias tests and confirms by the graphs that the mod200 of the SDS1104X-E does not have much alias rejection.
https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg1635386/#msg1635386
But the measurements were limited to 500MHz. I was very curious about alias response above 500MHz to see if there is a decent pre-ADC low-pass.
Thus, I did pretty much the same frequency measurements as in Reply# 829 but swept up to 1GHz.



Figure 1:
The graph shows the Frequency response from 5MHz to 1000MHz of the SDS1104X-E using the 2/4-Channels switched to 500MBs. I used the FFT-Mode (MATCH) and put the results into Excel.
The green X-Axis arrows below shows the actual Oscilloscope frequencies (the frequency that the scope shows).
I divided the measurements into four sections (5-250MHz, 250-500MHz,500-750MHz. 750MHz-1000MHz) and patched each Scope-reading (0-250MHz) into the one graph. I flipped the x-Axis of the sections 250MHz-500MHz and 750MHz-1000GHz because an RF input of 251MHz maps to an alias frequency at the scope reading of 249MHz etc.. 

The blue curve shows the original  SDS1104 (out of the box) frequency response from 5MHz to 1000MHz. You can see additional rejection above 100MHz which mirrors  at the Nyquist frequency of 250MHz and 750MHz. Because the rejection mirrors at Nyquiwst, it must be a DSP filter (not only the RF inputs mirror at Nyquist, but also any internal DSP filter).
The red curve shows the response after applying the mod200 software change for frequency extension to 200MHz. Since that response shows no mirror-effects (it falls monotonically) there cannot be any DSP filter applied. The rate at which the response includes any filtering applied to prior to the ADC. Because the blue and red curve align, except for the DSP-filter, I am presuming that nothing is switched in the hardware when applying the mod200 software change. Since the red curve resembles earlier measurements of the SDS1202 (Performa01 in Reply# 817), it kind of proves that the hardware is identical between SDS1104 and SDS1204.



Figure 2:
The graph shows the Frequency response from 5MHz to 1000MHz of the SDS1104X-E using the 2/4-Channels switched to 1GBs. I divided the measurements in two sections (5-500MHz, 500MHz-1000MHz) and patched each Scope-reading (0-500MHz) into the one graph. I flipped the x-Axis of the section 500MHz-1000GHz.
The blue curve shows the original  SDS1104 (out of the box) frequency response from 5MHz to 1000MHz. You can see the great rejection above 100MHz which mirrors  at the Nyquist frequency of 500MHz.
The red curve shows the response after applying the mod200 software change for frequency extension to 200MHz. Since that response simply falls monotonically there can’t be any DSP filter applied. Because the blue and red curve align, except for the DSP-filter, I am presuming that nothing is switched in the hardware when applying the mod200 software change.

Conclusions:
  • The software upgrade mod200 does not seem to switch any input ADC filtering.
  • The hardware of the SDS1104 and SDS120X seem to be identical and no matter of license mode.
  • In SDS1004 mode, there is a DSP filter above 100MHz which rejects aliasing up to Nyquist and beyond Nyquist because the DSP filter also mirrors around the first Nyquist frequency.

But I am still stuck with my earlier question: Why is the alias frequency rejection of the 200MHz mode so bad? I am not sure if a better (steeper) hardware LPF filter could be designed to reject at least the 500MHz better.
And more importantly: why don’t they not even apply DSP filtering at 1GB/S sample-rate to the SDS1204 (SDS1104 with mod200)?? At 1GB/s sample rate they could have applied the same DSP filter as for the SDS1004 in 500MB/s mode. I would presume that this does not even need a hardware change. What am I missing? What are other Oscilloscopes doing?


« Last Edit: April 07, 2019, 12:39:04 pm by Lazyengineer »
 

Online HendriXML

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1272 on: April 19, 2019, 09:48:41 pm »
https://www.eevblog.com/forum/testgear/using-a-awg-and-a-scope-do-a-low-voltage-level-characterization-of-a-1n4005/msg2354547/#msg2354547
While progressing in the above thread I found a repeating glitch in my graph. My side tracks will not be interesting for everybody, but there seems to be something funny going on with my Siglent SDS1104X-E. It may not be a huge deal, but it might also be a firmware kind of issue and thus solvable.
So if any owners want to have a look at it, be my guess.
« Last Edit: April 19, 2019, 10:10:15 pm by HendriXML »
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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1273 on: April 19, 2019, 10:00:51 pm »
You have a consistant shift at the same location, so try changing the vdiv of the scope, if it happens at the same voltage then its something weird, if it happens at the same relative position then its the ADC having an in spec non linearity error, similar to a missed code,

To better research what is going on when we see what influences it, we can use the VGAC command to manually set the VGAC amplification, C1:VGAC? get the number then increment it by 1 or more, then set it back with C1:VGAC n ,
 

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1274 on: April 19, 2019, 11:16:24 pm »
You have a consistant shift at the same location, so try changing the vdiv of the scope, if it happens at the same voltage then its something weird, if it happens at the same relative position then its the ADC having an in spec non linearity error, similar to a missed code,

To better research what is going on when we see what influences it, we can use the VGAC command to manually set the VGAC amplification, C1:VGAC? get the number then increment it by 1 or more, then set it back with C1:VGAC n ,
Ah nice, more SCPI commands. Is there a resource where this one comes from? I’m still looking for the command that turns segmented mode on, and the nr of segments. Besides that, most of the testing goes automatically. Which is quite the time saver.
Does turning the knob in fine mode also change the VGAC (a new concept to me, have research it sometimes), I alway thought it was (software) value scaling, and did not use it for that reason.
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