Author Topic: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes  (Read 149989 times)

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Offline rf-loop

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1175 on: January 07, 2019, 07:02:34 pm »
Thanks for the practical examples helping novices how to work with Acq.ON more (Sequential).
That was the thing I was trying to figure out this week by it was not intuitive and the manual didn't help from the first try.

Could somebody advice on how use 1204/1104xe for tracing a problem witch require ideally "data logging" of 2 hours the turn marker of 200-1500 RPM rotating shaft.
I am able to check with a scope that in ideal conditions turn marker only one pulse per turn. But equipment tends to give not systematic failures over 1-2 hours of work cycle.
There is the idea that either some voltage fluctuations at line \ ground or vibrations (or both) make false/absent rotation pulses. 

Ideally, I need to get 1-2 hours triggers on all pulses and save that data to compare with a time of equipment errors in the final image (equipment is drum scanner and faults to trace are "dead" lines of pixels in the final scan that appear not always and so still are not identified by source).

I was reading in the manual for older Siglent scope model _CML about RECORD function where it is possible to write all untriggered screens with specified time intervals up to 2500. Could 1204xe make such a trick in some mode - it has much better memory than _CML scope model?

CML Record function is very extremely different what is in modern SDS1000X and X-E series.
CML records TFT frames, up to 2500 and with user settable interval. (There is also "Recorder" in CML but it have 6M memory and it can record low samplerates continuously up to 6Msamples, but it is so very long time I have used CML that it is better I do not try tell how it works.

SDS1000X-E
It can save up to 80000 trigged waveforms. (normal mode to wavefrom history buffere FIFO, woreking always in bacround. OR in special Sequence mode to this same history buffer. In sequence mode scope do not handle any other processes  what may  lead to loose some trigger event so it also do not display during this Sequence until whole sequence is ready)



Odd but still principle itself is valid.






Old but principle itself is still valid.







Next image show amount of history and sequence mode segment memory







How ever acquisition is made to history buffer (normal or sequence mode)
Every single acquisition (every single horizontal sweep) is time stamped. If there is 80000 or 2 acquistions in buffer every have time stamp (but there is not real time clock in system so time of clock is not true time but time between acquisitions is accurate)




(example of time list. User can select what segment (frame) he want look. Also it need note that this do not save image memory, it save ADC data and every segment (frame) is current memory length in use. This is why all can post process including interpolation and math and measurements, even run mask test.

----
But now your problem.
If you want only record time interval list when trigger have occured (scope have detected pulse) you can record 80000 time stamps.
Just set scope to trig this pulse. Set trigger so that it trig when pulse signal meet some your specified values.
For max count of events. Then set scope for 10ns/div and select sequence mode with max 80000 segments. Yes in this case waveform length is only 140ns. You can not see your pulse (perhaps part of rise edge or?) but every time it meet trigger, it make acquisition and write time stamp for it.

But, now, even with this if your speed is constant 1500rpm and one pulse per turn you get 80000 time stamps. 80000/1500=53,3 minute. With this speed, over this time you have time stamp (including time after last event aka interval) from every single trig. You can watch if there is missing trig (missing pulse as trigger setup have defined what us "pulse").
But not alone this. Other channel(s) can also be in use and also data from these is saved same time (example one may watch some point voltage etc)
But then, if you want also see your whole pulse there need use much more long length for one acquisition.
If think your max speed even with this 1500rpm  one turn is 40ms. I do not know anything what kind of sensor you have for pulses and how long is your pulse with minimum and maximum speed (200 - 1500rpm) perhaps we talk milliseconds.

This is only imagination. If think your pulse width 36th of turn (10 degree) then pulse width is roughly between 10ms to 1ms.
Ok, perhaps then 1ms/div is ok for look whole pulse.
If want look maximum amount of pulses what can record using normal history or sequence mode. If reduce memory length to 7k and t/div is 1ms and then sampling speed is 500kSa/s (samples interval 2us). Maximum amount is 3912 this kind of waveforms stored in memory (in 4 channel model 4 channel parallel)
with 1500rpm this is only 2.6 min. and 200rpm it is 19.5 min. (but of course time resolution is still good and lot of more than needed)


But this is not alone what can do. But this is not for your case.

Example. If want longest record, lowest samplerate and with some time gap between records
It can do (extreme limit) 5 sample per second
Limit memory length (acquisition length) to 7k
Set 100s/div3
Now one acquistion time lenght is 100s*14 = 1400 seconds 231/3min
and now it can also record 3912 of these, total 63 days long sum of data but total time more.  As told, between these 231/3min records there is gap. I have not checked now and I'm not sure if I remember right but gap is around one horizontal div so in this case ~100s gaps. So total time is even more than 63 days
Of course selecting optimal time base and optimal one acquisition length there can fid solution for many kind of needs, but of course not for all needs.


Old times I have been working in factory where we need always analyze and find some mysterious errors in lot of different machines and processes. Of course there we have analog and digital data recorders, scopes, spectrum analyzers and so on...  of course because if manufacturing stop due to some failure in machines it is hundreds or "sky is limit" times more expensive than some electronic test equipments. But still, in many cases. Because time is money and specially, "less time = save more money".
There was golden rule. Do it simply!  Do not waste time for finding this and that and for nice analyzators and scratching head how I use this for remove this problem in important machine.

One solution is that you install reliable extra detector one pulse per turn . (what ever even simplest but reliable, example some  proximity sensor) then trig scope with it and watch that with every this pulse appear also this pulse what you suspect. After you find more what happen there you can analyze just this situation where failure happen, example watching some drop outs etc.
With extra sensor you can even simple trig only when it fails.
Of course if your shaft speed is constant this is extremely easy just with normal trigger functions without any extra but your speed change between 200-1500rpm so this need some things what can "remove" this speed change affect. One is just extra sensor. Most easy if you have available it.

But then, do you like analyze it because analyzing something is so nice... or repair it now or better if yesterday....

Example about other kind of thinking. Of course this is trivial example and perhaps not at all for your case...  but some times we need break thinking some locked or circle paths in our brain and find other thinking paths for find solutions. Some times solutions are even extremely simple after it pops up.
Think example what happen there when one pulse pulse is missing. What it do in this case and can you use this information... you know digital scope is always doing pretrigger sampling until trigger... so you can easy get what happen before something has happened. If you can detect (failure) result then you can analyze what happen before...  just tip for change thinking method to reverse (cousin of this is negation test in thinking process)


For siglent there something in wish list.

100s/div is now slowest.

It can change to  1000s/div or even 10000s/div  (roll mode 100Sa/s and normal mode 1kSa/s)
This need only some bytes in FW. 
Some competitors have it.
There have been many times some questions about more long time data recording.

Even with these extra slow sample rates it can directly save continuous wfm to USB. There is now lot of processing power for it.

It was long long time ago even SDS1000CML can do it when very slow samplerate, directly to USB (I do not know when they have take it off)

Now there is processing power, SDS1kXE can easy do much more this kind of things. More slow t/div andf also direct unlimited length capture to USB if sample rate is enough slow. 
It is not only one people who need more long capture times or even like very long time data logger without time gaps.







« Last Edit: January 08, 2019, 06:11:00 am by rf-loop »
If practice and theory is not equal it tells that used application of theory  is wrong or the theory itself is wrong.
It is much easier to think an apple fall to the ground than to think that the earth and the apple will begin to move toward each other and collide.
 
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Offline rf-loop

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1176 on: January 07, 2019, 07:07:28 pm »
Don't know about 28M of data?? Its only 14M to me per channel pair, with both pairs tied to the same trigger? unless I am really missing something,
When monitoring all four channels at an appropriate time base = 28 Mpts of captured data.

In 4 channel model even 109Mpts captured data (in history or sequence)  ;D
If practice and theory is not equal it tells that used application of theory  is wrong or the theory itself is wrong.
It is much easier to think an apple fall to the ground than to think that the earth and the apple will begin to move toward each other and collide.
 

Online Rerouter

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1177 on: January 07, 2019, 08:14:51 pm »
rf-loop, would you be willing to go into exactly what bytes need to be changed for the longer modes? I can only see 1000s for the upper and 200ps and 500ps unused for the lower, as strings in the app? while I'm curious about those lower time bases, I would love to know what the modification procedure is.
 

Offline rf-loop

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1178 on: January 07, 2019, 09:31:50 pm »
rf-loop, would you be willing to go into exactly what bytes need to be changed for the longer modes? I can only see 1000s for the upper and 200ps and 500ps unused for the lower, as strings in the app? while I'm curious about those lower time bases, I would love to know what the modification procedure is.
Individuals mods are very much other things. ;) And as told previously these things are better to discuss in dedicated thread for these...  example here : https://www.eevblog.com/forum/testgear/sds1104x-e-hack-to-200mhz-and-full-options/

or here: https://www.eevblog.com/forum/testgear/unlocking-siglent-sds1104x-e-step-by-step/msg1788704/#msg1788704



Firmware development is Siglent work.  It need add to product features.
It is Siglent work to develop products better and better and add features or develop some features better. Of course in priority order. First "immediately" fatal bugs if exist
Then 2nd level bugs
Then some finishing/grinding UI and also adding some features or change some limits (as example add 200, 500 and 1000s/div and also wish they add one more short max memory limit selection (now they are 14/7M, 1.4M/700k, 140k/70k and 14k/7k) and I like if there is also 1.4k/700 selectable. (it give more freedom for history/segmented)

I do only that I write wish list to "Santa Claus" (in this case Siglent) and then waiting christmas.
« Last Edit: January 07, 2019, 11:33:33 pm by rf-loop »
If practice and theory is not equal it tells that used application of theory  is wrong or the theory itself is wrong.
It is much easier to think an apple fall to the ground than to think that the earth and the apple will begin to move toward each other and collide.
 

Offline tinhead

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1179 on: January 08, 2019, 08:28:17 am »
i found small bug, only CH1 and CH3 affected, only when CH2 and CH4 are off. In fine adjust mode, 302mV/DIV is on wrong position. Seems to be only the case as well memory ans timebase dependent (14M 1ms->1ns, 1.4M 100us->1ns, 140k 10us->1ns, 1.4k 1us -> 1ns).

Tested on 8.1.6.1.26, hw1.3


EDIT: hmm, there is actually more like that, 1.54mV/DIV to 1.50mv/DIV, then very strange jumps/no move from 1.36mV to 780uV/DIV, then the wave jumps down by 2 DIVs down between 770uV/DIV and 750uV/DIV. Same as above, dependent on timebase and memory settings, this time CH1 more affected than CH3, no problem with CH2 and CH4.

Can someone check that? My DSO is for sure properly calibrated and still under quick warranty, so maybe i have to replace it.
« Last Edit: January 08, 2019, 08:55:36 am by tinhead »
I don't want to be human! I want to see gamma rays, I want to hear X-rays, and I want to smell dark matter ...
I want to reach out with something other than these prehensile paws and feel the solar wind of a supernova flowing over me.
 

Online Rerouter

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1180 on: January 08, 2019, 12:03:20 pm »
Around the weird steps would you be able to run the scpi command c1:vgac? This will return the setting for the variable gain amplifier. And will give insight into if its the adc scaling at that point or the vga
 

Offline rf-loop

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1181 on: January 08, 2019, 03:34:23 pm »
i found small bug, only CH1 and CH3 affected, only when CH2 and CH4 are off. In fine adjust mode, 302mV/DIV is on wrong position. Seems to be only the case as well memory ans timebase dependent (14M 1ms->1ns, 1.4M 100us->1ns, 140k 10us->1ns, 1.4k 1us -> 1ns).

Tested on 8.1.6.1.26, hw1.3


EDIT: hmm, there is actually more like that, 1.54mV/DIV to 1.50mv/DIV, then very strange jumps/no move from 1.36mV to 780uV/DIV, then the wave jumps down by 2 DIVs down between 770uV/DIV and 750uV/DIV. Same as above, dependent on timebase and memory settings, this time CH1 more affected than CH3, no problem with CH2 and CH4.

Can someone check that? My DSO is for sure properly calibrated and still under quick warranty, so maybe i have to replace it.

Tst 7.1.6.1.26 (and siglent have told to me that FW  first number 7 or 8 is just "do not care" when update FW if it is 7 or 8 but not told what is real difference (if any). My HW 00-03: Nothing like this.

My first opinion is: return it with note "fault on arrival" and short info about problem so that if seller is very bad like amazon or equal they do not sell it to next victim.



« Last Edit: January 08, 2019, 05:21:41 pm by rf-loop »
If practice and theory is not equal it tells that used application of theory  is wrong or the theory itself is wrong.
It is much easier to think an apple fall to the ground than to think that the earth and the apple will begin to move toward each other and collide.
 

Online Rerouter

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1182 on: January 08, 2019, 06:53:06 pm »
Yep, looks like there is something weird about the calibration for certain values, and seems to be related to VGAC it rolls over at 750uV, 1.50mV, 3.50mV, 7.50mV etc,

However the first 2 seem to have an error at the roll over. Equally it hints that it should be able to allow for as low as about 350uV / div on a hardware perspective. and up to about 12V/div on the upper,

To make clear, the C1:VGAC command is a com/query that you can use to manually set the variable gain amplifier, values between 15 - 199 seems to be the valid range used during device calibration, though it may be able to use the full 0-255, which would possibly allow all the way down to 300uV/div. room for imagination for anyone else who actually has gear to test accurate AC amplitude at crazy low amplitudes.

There is something else also being used during those step changes, but I have not yet found a command for it.

Below is the VGAC values for each vdiv step on my scope, you can see it goes a bit wonky at 750uV and 1.50mV

Code: [Select]
500uv 183
510uV   182
520uV   181
530uV 180
540uV 179
550uV 178
560uV 177
570uV 176
580uV 175
590uV 174
600uV 174
610uV 173
620uV 172
630uV 171
640uV 171
650uV 170
660uV 170
670uV 169
680uV 168
690uV 168
700uV 167
710uV 167
720uV 166
730uV 165
740uV 165

750uV 154
760uV 154

770uV 199
780uV 198
790uV 197
800uV 196
810uV 196
820uV 195
830uV 194
840uV 193
850uV 192
860uV 192
870uV 191
880uV 190
890uV 189
900uV 189
910uV 188
920uV 188
930uV 187
940uV 186
950uV 186
960uV 185
970uV 184
980uV 184
990uV 183
1.00mV 183
1.02mV 182
1.04mV 181
1.06mV 180
1.08mV 179
1.10mV 178
1.12mV 177
1.14mV 176
1.16mV 175
1.18mV 174
1.20mV 174
1.22mV 173
1.24mV 172
1.26mV 171
1.28mV 171
1.30mV 170
1.32mV 170
1.34mV 169
1.36mV 168
1.38mV 168
1.40mV 167
1.42mV 167
1.44mV 166
1.46mV 165
1.48mV 165

1.50mV 154
1.52mV 154

1.54mV 199
1.56mV 198
1.58mV 197
1.60mV 196
1.62mV 196
1.64mV 195
1.66mV 194
1.68mV 193
1.70mV 192
1.72mV 192
1.74mV 191
1.76mV 190
1.78mV 189
1.80mV 189
1.82mV 188
1.84mV 188
1.86mV 187
1.88mV 186
1.90mV 186
1.92mV 185
1.94mV 184
1.96mV 184
1.98mV 183
2.00mV 183
2.06mV 181
2.12mV 180

2.18mV 178
2.24mV 177

2.30mV 175
2.36mV 174
2.42mV 173
2.48mV 172
2.54mV 171
2.60mV 170
2.66mV 169
2.72mV 168
2.78mV 167
2.84mV 167
2.90mV 166
2.96mV 165
3.02mV 164
3.08mV 164
3.14mV 163
3.20mV 162
3.26mV 162
3.32mV 161
3.38mV 160
3.44mv 160

3.50mV 190
3.56mV 189
3.62mV 188
3.68mV 188
3.74mV 187
3.80mV 186
3.86mV 185
3.92mV 184
3.98mV 183
4.04mV 182
4.10mV 181
4.16mV 181
4.22mV 180
4.28mV 179
4.34mV 178
4.40mV 178
4.46mV 177
4.52mV 176
4.58mV 176
4.64mV 175
4.70mV 175
4.76mV 174
4.82mV 173
4.88mV 173
4.94mV 172
5.00mV 172
5.10mV 171
5.20mV 170
5.30mV 169
5.40mV 169
5.50mV 168
5.60mV 167
5.70mV 166
5.80mV 166
5.90mV 165
6.00mV 165
6.10mV 164
6.20mV 163
6.30mV 163
6.40mV 162
6.50mV 162
6.60mV 161
6.70mV 161
6.80mV 160
6.90mV 160
7.00mV 159
7.10mV 159
7.20mV 158
7.30mV 158
7.40mV 158

7.50mV 187
« Last Edit: January 08, 2019, 09:26:48 pm by Rerouter »
 

Offline bluejedi

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1183 on: January 08, 2019, 07:45:49 pm »
Some suggestions to Siglent about messages and captions on the screen.

1. The captions on the screen should be in front of the waveforms and not transparent or almost not transparent. Currently they often become unreadable when they are crossed by waveforms.

Clear suggestions for improving readability of text overlays were made before (July 2018) here:

https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg1713224/#msg1713224

Unfortunately @Siglent appears still not to care about this. The same holds for Wifi related bugs e.g. like described (July 2018) here:

https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg1708814/?topicseen#msg1708814
« Last Edit: January 08, 2019, 07:58:44 pm by bluejedi »
 

Offline bluejedi

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1184 on: January 08, 2019, 08:25:10 pm »
I do only that I write wish list to "Santa Claus" (in this case Siglent) and then waiting christmas.

Oh, please not Christmas because then we will have to wait for (almost) a whole year.  8)
 

Online Rerouter

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1185 on: January 08, 2019, 08:25:54 pm »
Ok, can confirm VGAC works from 1-255, with a code of 255 does make it display a hair shy of 300uV/div,

And a code of 1 on the 10V/div range makes the signal display at about 100V/div, dont have a signal source that high, so its approximate, no sure to what end someone would want to compress the signal at the higher end, but it exists,  ^-^
 

Offline rf-loop

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1186 on: January 08, 2019, 08:48:33 pm »
Yep, looks like there is something weird about the calibration for certain values, and seems to be related to VGAC it rolls over at 750uV, 1.50mV, 3.50mV, 7.50mV etc,

However the first 2 seem to have an error at the roll over. Equally it hints that it should be able to allow for as low as about 350uV / div on a hardware perspective. and up to about 12V/div on the upper,

To make clear, the C1:VGAC command is a com/query that you can use to manually set the variable gain amplifier, values between 15 - 199 seems to be the valid range used during device calibration, though it may be able to use the full 0-255, which would possibly allow all the way down to 100uV/div. room for imagination for anyone else who actually has gear to test accurate AC amplitude at crazy low amplitudes.

There is something else also being used during those step changes, but I have not yet found a command for it.

Below is the VGAC values for each vdiv step on my scope, you can see it goes a bit wonky at 750uV and 1.50mV

Code: [Select]
500uv 183
510uV   182
520uV   181
530uV 180
540uV 179
550uV 178
560uV 177
570uV 176
580uV 175
590uV 174
600uV 174
610uV 173
620uV 172
630uV 171
640uV 171
650uV 170
660uV 170
670uV 169
680uV 168
690uV 168
700uV 167
710uV 167
720uV 166
730uV 165
740uV 165

750uV 154
760uV 154

770uV 199
780uV 198
790uV 197
800uV 196
810uV 196
820uV 195
830uV 194
840uV 193
850uV 192
860uV 192
870uV 191
880uV 190
890uV 189
900uV 189
910uV 188
920uV 188
930uV 187
940uV 186
950uV 186
960uV 185
970uV 184
980uV 184
990uV 183
1.00mV 183
1.02mV 182
1.04mV 181
1.06mV 180
1.08mV 179
1.10mV 178
1.12mV 177
1.14mV 176
1.16mV 175
1.18mV 174
1.20mV 174
1.22mV 173
1.24mV 172
1.26mV 171
1.28mV 171
1.30mV 170
1.32mV 170
1.34mV 169
1.36mV 168
1.38mV 168
1.40mV 167
1.42mV 167
1.44mV 166
1.46mV 165
1.48mV 165

1.50mV 154
1.52mV 154

1.54mV 199
1.56mV 198
1.58mV 197
1.60mV 196
1.62mV 196
1.64mV 195
1.66mV 194
1.68mV 193
1.70mV 192
1.72mV 192
1.74mV 191
1.76mV 190
1.78mV 189
1.80mV 189
1.82mV 188
1.84mV 188
1.86mV 187
1.88mV 186
1.90mV 186
1.92mV 185
1.94mV 184
1.96mV 184
1.98mV 183
2.00mV 183
2.06mV 181
2.12mV 180

2.18mV 178
2.24mV 177

2.30mV 175
2.36mV 174
2.42mV 173
2.48mV 172
2.54mV 171
2.60mV 170
2.66mV 169
2.72mV 168
2.78mV 167
2.84mV 167
2.90mV 166
2.96mV 165
3.02mV 164
3.08mV 164
3.14mV 163
3.20mV 162
3.26mV 162
3.32mV 161
3.38mV 160
3.44mv 160

3.50mV 190
3.56mV 189
3.62mV 188
3.68mV 188
3.74mV 187
3.80mV 186
3.86mV 185
3.92mV 184
3.98mV 183
4.04mV 182
4.10mV 181
4.16mV 181
4.22mV 180
4.28mV 179
4.34mV 178
4.40mV 178
4.46mV 177
4.52mV 176
4.58mV 176
4.64mV 175
4.70mV 175
4.76mV 174
4.82mV 173
4.88mV 173
4.94mV 172
5.00mV 172
5.10mV 171
5.20mV 170
5.30mV 169
5.40mV 169
5.50mV 168
5.60mV 167
5.70mV 166
5.80mV 166
5.90mV 165
6.00mV 165
6.10mV 164
6.20mV 163
6.30mV 163
6.40mV 162
6.50mV 162
6.60mV 161
6.70mV 161
6.80mV 160
6.90mV 160
7.00mV 159
7.10mV 159
7.20mV 158
7.30mV 158
7.40mV 158

7.50mV 187

Nice findings.


And then one small pick-up: "....has gear to test accurate AC amplitude at crazy low amplitudes." ;)

100uV class is not crazy low even if it is peak to peak (around -76dBm what is quite strong signal (in radio). Normal good rf generators goes usually down to well below -127dBm (100nVrms) This my one old "33kg junk" goes down to -140dBm (23nVrms)

One tiny experimental playing like kid.
Using higher level as external trig Ch4 and measured in Ch1 just using 500uV/div and 129MHz signal -72dBm, nicely  without big error (256 acquisition  average) Gen out -72dBm and SDS1204X-E display signal level Stdev (ac rms) 53uV. This trigger method need because of course it can not trig directly this kind of low signal what was measured in Ch1. 
Also this need high amount of trace averaging for get any useful signal out from noise to display, but with continuous signal it is possible.



But then bac out from "just fun"  playing.
Also it need think reality. Reality is that this kind of oscilloscope input and front end have quite LOT of noise if think these low signals. It is never designed as SA or radio front end. First thing is that even when there is AC/DC selection front end amp is dual pathway DC coupled and LF (specially 1/f) noise is huge due to many reasons. Then it is also for 1Mohm input.  Even when these cheap scopes have 50ohm inputs front end is still 1M. How much is 1Mohm Johnson noise alone.
Even this 500uV/div is borderline but still useable. If we amplify this noise more... what we get.
Front end is totally different animal if it is designed for -80 or -100dBm range...
500uVp-p is roughly -62dBm in 50ohm system.

Perhaps it is more wise to use preamplifier if oscilloscope really need look this kind of low level signals. Most oscilloscopes normal  most sensitive range is around 2 - 5mV/div (full resolution) and with reason(s).
« Last Edit: January 08, 2019, 08:52:34 pm by rf-loop »
If practice and theory is not equal it tells that used application of theory  is wrong or the theory itself is wrong.
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Online Rerouter

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1187 on: January 08, 2019, 09:11:57 pm »
I chose my wording poorly, but for me that is low amplitude in the realm of a scope. And while I have plenty of signal sources, I lack any direct way to measure amplitudes that low with any hope of accuracy.

I agree its pretty noisy down at the 500uV range, however It works on all attenuation ranges. so you can abuse it to view smaller signals on the larger offset ranges, e.g. 8mV / div at a +-21V offset range. or 70mV/div at a +-210V offset range, this is where I see it being much more useful,  >:D
 

Offline rf-loop

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1188 on: January 08, 2019, 11:05:33 pm »
I chose my wording poorly, but for me that is low amplitude in the realm of a scope. And while I have plenty of signal sources, I lack any direct way to measure amplitudes that low with any hope of accuracy.

I agree its pretty noisy down at the 500uV range,

We can say it is very npisy. But also we can say it have very low noise. It depends context. When we talk roughly this class of oscilloscopes it can say it have low noise. Compare to Rigol, compare to Keysight, compare to... ~30uVrms 100Mhz BW is not at all bad.


@srce: https://www.eevblog.com/forum/testgear/oscilloscope-input-noise-comparison/msg1964747/#msg1964747


200MHz model


Compared 100MHz vs 100MHz, settings are comparable.



however It works on all attenuation ranges. so you can abuse it to view smaller signals on the larger offset ranges, e.g. 8mV / div at a +-21V offset range. or 70mV/div at a +-210V offset range, this is where I see it being much more useful,  >:D

Can you explain it bit more. Perhaps I now have a brain short circuit and I don't understand.
If practice and theory is not equal it tells that used application of theory  is wrong or the theory itself is wrong.
It is much easier to think an apple fall to the ground than to think that the earth and the apple will begin to move toward each other and collide.
 

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1189 on: January 09, 2019, 05:05:27 pm »
Ok, the simplest way to demonstrate it for yourself would be, set your scope to 200mV/div, this will click over the attenuator so its in the +-21V offset range, now at this point, the VGA for the front end is barely amplifying at all, with a VGA (variable gain Amplifier) code around 30,

The higher the code, the higher the amplification,

Now with it like that, sending "C1:VGAC 255" over SCPI (or webserver) will set the VGA to maximum amplification, which is about 8mV/div for my device, As I dig into the device calibration, Its possible we can figure out exactly what it is for each code, I should point out its more noisy than the actual 5mV/div range, but if you need it on a bigger offset, then the scope can indeed do it.

This will revert if you change the channel offset or vdiv manually, The increased offset range comes from the "C1:DACC" command I documented earlier, you have a bit of extra offset range at both ends,

This just leaves some other attenuation / amplification happening in the chain when the VGAC code rolls around, I suspect its to do with the "C1:DAC_ATTEN_SET" command, Haven't documented it, but its in the same decision tree as the other 2, so once I have him nutted out, there may be a little more we can abuse.
 

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1190 on: January 11, 2019, 08:13:35 pm »
More digging, the VGAC command directly sets the fine gain register for the VGAC which is an AD8370, And some further digging confirms there is a roll over in the middle which is the switch from low gain mode to high gain mode.

So my example of 8mV/div on the 20V offset range is amplified to 52 V/V, and does show similar noise to the 500uV range, which makes sense when its amplifying that much.
Now that we know this, Its not hard to extrapolate out any intermediate V/V of gain if you need an odd measurement

https://www.analog.com/media/en/technical-documentation/data-sheets/ad8370.pdf
 

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1191 on: January 12, 2019, 12:10:53 pm »
And finally, an explanation for the quirk with the fine gain calibration, at 750-760uV and 1.50-1.52mV its an overflow based on how they limited there calibration routine, At these points the VGAC code is meant to be greater than 199, but in how they have implemented things, that results in it defaulting to 154 when it cannot find a matching record.

 

Offline tmbinc

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1192 on: January 15, 2019, 06:14:28 am »
Not sure if this had been posted here, but the analog frontend was reverse-engineered:

https://github.com/360nosc0pe/siglent_hardware/tree/master/sds1202xe/siglent_AFE

The gain setting is a combination of the VGA setting, the ADC settings and the shift register:


### AFE (analog front-end) setting
Each channel of the scope contain one 74HC595 shift out register powered by 5V.
Five of the eight outputs are used to change hardware settings in the AFE:

    595_QB:  First divider, 10:1, active high
    595_QC:  Second divider, 10:1, active high
    595_QD:  AC coupling, low = AC, high = DC
    595_QE:  PGA enable, active high
    595_QF:  BW limit, low = 20MHz, high = full



From my notes: (Sorry about the formatting)

ADC is the write to reg 0x2B of the HMCAD1511 ADC (Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/hmcad1511.pdf), the "coarse gain" register. Value is in dB (actually). ShiftReg is the value written to the frontend shift register. VGA is the value set to the VGA.



         ADC ShiftReg ADC VGA
  5mV   2B 09   78   +9  B9
 10mV   2b 06   78   +6  B9
 20mV   2B 04   78   +4  B9
 50mV   2b 02   78   +2  AD
100mV   2B 00   78   +0  AD
200 mV  2B 04   78   +4  27
500 mV  2B 00   78   +0  3f
  1v    2B 00   78   +0  1F
  2V    2B 04   7A   +4  29
  5v    2B 00   7A   +0  41
 10V    2B 00   7A       21
 20V    2B 04   7E       28
 50v    2B 04   7E       41
100V            7E       20

 

Offline tautech

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1193 on: January 15, 2019, 07:13:37 am »
Not sure if this had been posted here, but the analog frontend was reverse-engineered:
This is a better thread for SDS1202X-E stuff:
https://www.eevblog.com/forum/testgear/the-_official_-siglent-sds1202x-e-thread/
Avid Rabid Hobbyist
 
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Offline tinhead

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1194 on: January 15, 2019, 07:13:56 am »
Not sure if this had been posted here, but the analog frontend was reverse-engineered:

https://github.com/360nosc0pe/siglent_hardware/tree/master/sds1202xe/siglent_AFE


i don't think this has been properly done, look at this part:

I don't want to be human! I want to see gamma rays, I want to hear X-rays, and I want to smell dark matter ...
I want to reach out with something other than these prehensile paws and feel the solar wind of a supernova flowing over me.
 

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1195 on: January 15, 2019, 09:21:08 am »
Thanks for that tmbinc. That explains the 2B value I keep seeing around ADC calibration. Now to just determine how to change it via scpi.

As it notes its calibration as X1 X10 and X100. That explains some of the weirdness I have been seeing. If i can read or write them. Well there is a part of the calibrarion routine that gives up on correcting the Dac offset. Amd that would let me verify if the values end up used.
 

Offline Andreax1985

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1196 on: January 29, 2019, 10:50:55 am »
I need to measure AC ripple on a 320V DC signal using AC coupling mode. SDS1004X-E input is rated for 400Vpk. Is this enough for my needs? (My worry is due to the fact that 400Vpk correspond to 280Vrms...)
 

Offline Martin72

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1197 on: January 29, 2019, 11:02:47 am »
At this voltage rate you should use a differential or a 100:1 probe.


 

Offline Performa01

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1198 on: January 29, 2019, 06:38:15 pm »
I need to measure AC ripple on a 320V DC signal using AC coupling mode. SDS1004X-E input is rated for 400Vpk. Is this enough for my needs? (My worry is due to the fact that 400Vpk correspond to 280Vrms...)
It heavily depends on the exact waveform what 400Vp actually corresponds to. For DC however, peak and rms are identical.
So with 320VDC you got 80Vp headroom left. That means that the ripple must not exceed 80Vp, but I would think if it is anywhere near that much, then there would also be no need to maximize the sensitivity (and use x1 probe factor) either.
 

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Re: Siglent SDS1104X-E and SDS1204X-E Mixed Signal Oscilloscopes
« Reply #1199 on: January 29, 2019, 07:30:47 pm »
I should also point out probes have there own voltage ratings, looking on the side of a random one I have on hand (X1: 150V, X10: 300V) its not a siglent probe, so check yours first.

If the probe cannot handle the voltage, but the scope can, it means you will just have to use a coax cable to measure it.
« Last Edit: January 29, 2019, 07:33:54 pm by Rerouter »
 
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