The Siglent SDG2042X Thread

[Bad_Driver]

During reading this board I noticed in the earlier posts that there is a way to set output level units to "dBm".
I scrolled thru every menu and thru the whole manual but I couldn't find how to do that. 
Help needed!

I also read in the other board that the cheaper SDG1000X series can calculate the right output voltage with dBm for any load (50 to 100kohms) but the SDG2000x not. But there is also nothing
in the SDG1000X manual (I thought I could use this for the SDG2000X)

To have that would be a big advantage for me (600 ohms dBm units output for audio). With newer/upcoming firmware???

How to set units to dBm? Sorry for that dumb question.

[tautech]

During reading this board I noticed in the earlier posts that there is a way to set output level units to "dBm".
I scrolled thru every menu and thru the whole manual but I couldn't find how to do that. 
Help needed!

I also read in the other board that the cheaper SDG1000X series can calculate the right output voltage with dBm for any load (50 to 100kohms) but the SDG2000x not. But there is also nothing
in the SDG1000X manual (I thought I could use this for the SDG2000X)

To have that would be a big advantage for me (600 ohms dBm units output for audio). With newer/upcoming firmware???

How to set units to dBm? Sorry for that dumb question.
Is there a change

Set the output to 50 ohm impedance then dBm units become available to select.

[Bad_Driver]

Thanks Tautech, I use 50ohms output, but how do I the unit change?
I can’t find it. Have you any further advice or picture of the screen?

Sorry to come up with such an question but a hint in the manual would be helpful.

[Bad_Driver]

I found the answer in the SDG6000 manual.
With numeric keyboard ....

Thanks again!

[tautech]

I found the answer in the SDG6000 manual.
With numeric keyboard ....

Thanks again!

Wondered how long it might take you. These things are best remembered when you find it for yourself. 

Yes just set a value with the keypad and then set the unit type from the selection available.

[Messtechniker]

Got myself a Siglent SDG2042X
Has the latest firmware. No need for me to pimp this thing to 120 MHz.
Got it from Meilhaus via UPS with a 6% discount.
28 hours and 16 minutes elapsed from the ordering click
to hitting the power button.
Currently just messing looking around. All seems to be well.

Software version is 2.01.01.35R3B2
Hardware version is 02-02-00-40-00

[Messtechniker]

So there it is now sitting on my bench.  The latest embodiment of the famous Siglent SDG 2042X. Put it through its paces over the last 3 days. All is well, doing its thing. But I did note a few things which might be added or improved.

1.) There is no means of dumping the screen to a locally connected USB stick. Yes, I have found the python script to do a screen dump on a PC over the network.

On the topic of SI Units compliance:
2.) To assign names to stored data files no lower case characters are available.
3.) Inconsistent use of the space character in the GUI. Just checked R&S and Keysight. They are in the same club.

Just to quote Wikipedia:

General rules
General rules for writing SI units and quantities apply to text that is either handwritten or produced using an automated process:
The value of a quantity is written as a number followed by a space (representing a multiplication sign) and a unit symbol; e.g., 2.21 kg, 7.3×102 m2, 22 K. This rule explicitly includes the percent sign (%) and the symbol for degrees Celsius (°C).[Exceptions are the symbols for plane angular degrees, minutes, and seconds (°, ′, and ″, respectively), which are placed immediately after the number with no intervening space.

4.) System Info gives the number of boot cycles. Giving the number of operating hours would be more useful. Probably impossible because there is no RTC.

5.) In sweep mode there is no means of outputting a signal corresponding to the momentary frequency.  I.e. a 0 to 5 V ramp, for example at a connector on the rear or through channel 2. Same applies to many even more expensive generators from R&S or Keysight for that matter.
Moreover, there is no SCPI command to query the frequency while sweeping.
Such a signal would be used for the X-axis when doing frequency response plots.

6.) Fat NI-Visa thing.  Does not matter much to me because I’ll probably never have to use it.

7.) Fan noise is probably normal. It’s audible and I don’t like it.  I know I am oversensitive to fan noise, so forget it.


Even so, I am a happy camper.

[jhenderson0107]

... . Yes, I have found the python script to do a screen dump on a PC over the network.

Please provide a link to that script. 

[Messtechniker]

Here:

https://gist.github.com/mobilinkd/8a07cc124946c87715c6a1458118411e

[jhenderson0107]

That's for the Siglent Scope, not the generator.  I haven't been able to find a means of retrieving the generator's screen. 

[adamgreig]

My script for screenshotting an SDG2042X is attached, but it looks the same as the previously posted script, i.e. uses the SCDP command. Definitely works on the SDG.

[jhenderson0107]

Thanks to you both.  I'll give it a try. 

Update: Tried it - works like a champ. 

Here's a link to a minimal control program for the SDG2042, SDG5162 and Rigol DG800/900:
https://www.dropbox.com/s/it3yiq9v2m4ppj8/Arb.7z?dl=0

[Thebrakshow]

I seem to be facing an interesting issue automating my SDG2042X via USB/Python and wanted to see if anyone could offer some insight since this is my first time automating lab equipment. My goal for this project is to set the ABW to either the Cardiac waveform or the ECG1 waveform (M24 and M85... both of the programming manual reference these built in waveform incorrectly BTW. that's off topic though). I want to vary the frequency every 1 second (1Hz to 3Hz with 16.6667mHz steps). The exact time interval is not crucial, what is crucial is that when the AWG receives a command to switch freq that it does so at the beginning of a cycle (or the end). What I'm noticing is that the AWG is switching immediately (no regard to current position of waveform cycle) so its leaving me with runt cycles. This is causing a lot of erroneous data since my circuit is reading the time R/R time intervals of the cardiac waveform (simply put, the time between the large spikes in a cardiac wave form).

my python script uses the ARWV command to set the gen on the correct wave form

Code: [Select]

dev.write('C1:ARWV INDEX,24')Then I use a simple while loop to increment and decrement the frequency with the basic wave command BSWV

Code: [Select]

dev.write('C1:BSWV FRQ,xxxx')where xxxx is a float variable

Does anyone know how I could avoid this issue? or maybe there is a command that I'm overlooking that would queue the command and execute them on the beginning of a wave's cycle?

Also I'd like to note that, yes I could just use the ramp function and set the symmetry to 50% (this works perfectly without the issue i'm facing) however, the goal for the future is to vary the frequencies in a particular/pseudo random way.
Thanks for any help!
-Brak

[TurboTom]

Instead of using the sweep function to ramp the signal frequency, could you possibly frequency modulate the signal and use a very slow noise signal (random) for that? Or even use the other channel as a modulation source (maybe in DC mode) and program this externally to provide your required ECG frequency? Just a few ideas that may be more complex but might lead to the functionality that you need.

[Messtechniker]

Been extensively using my SDG 2042X over the past weeks to repair a well damaged R&S UPGR Phsophometer. Some repair details on the Wellenkino site in German only. Thus some remarks on the SDG 2042X:

1.) The button lights are not bright enough in slightly elevated lighting conditions. Thus it is not easily possible to see if the Output button has inadvertently been turned off, for example. Briefly caused a bit of panic confusion.
2.) Amplitude unit is dBm. For Audio we prefer dBu.
3.) Max. unbalanced output is +19 dBu in the audio range. + 20 dBu would have been more convenient. Of course with Channel 2 phase inverted one gets 6 dB more balanced. But this is a workaround.
4.) Glad that I don't necessarily need to use the touchscreen. I for my part prefer the buttons.
5.) Frequency and amplitude accuracy is good enough for audio work. Distortion performance is not. But that was clearly stated in the published specs. So no surprises in this area.

[rf-loop]

Been extensively using my SDG 2042X over the past weeks to repair a well damaged R&S UPGR Phsophometer. Some repair details on the Wellenkino site in German only. Thus some remarks on the SDG 2042X:


2.) Amplitude unit is dBm. For Audio we prefer dBu.

Amplitude unit dBm  is  power. 0 dBm = 1mW
Universal dBm do not define what is impedance, it only tell power related to 1mW.
"Normally" it is used in 50 ohm RF systems.

dBu is Voltage level and its u come from "u = unloaded"  and why 0dBu is around 0.775Vrms all can find these audio explanations, internet is full of these.

There is one case when SDG2000X can use as it have dBu when you read dBm as dBu but only tightly in one case.

SDG2000X internal output impedance is fixed 50 ohm as usually all this kind of generators.
When user select SDG for HiZ load then level (voltage) is displayed for no load situation in output terminal. In this case user can not select dBm because impossible (infinite R).

When there is some load example 1Mohm scope input or Probe tip load effect is so low it do not need correct.
If there is some other load example 50ohm now, as ohm's law, output is half... inside 50 ohm series with outside 50ohm and Voltage over outside load is half what is displayed. But if you tell to SDG that load is 50ohm then it can correct numbers and display right.  SDG menu can select Hi-Z or Load. DEFAULT is that Load if 50 ohm. But user can also select this load value. If  load is 60 ohm then select 60 ohm and again voltage is displayed ok and also power is displayed ok. Just set true used load and all is displayed ok.


But then this audio levels mess. How world have gone to this mess I do not know and I do not want know. But this is where we need live. 
http://www.sengpielaudio.com/calculator-db-volt.htm


dBu as far as I remember is somehow defined for 600ohm. There is a lot of history behind the 600 Ohm audio transmission standard. Today sometimes looks like no one anymore care this golden "standard" 600 Ohm.

0 dBu = 0.775Vrms volts and in 600ohm system is power is just 1mW, same as 0 dBm is 1mW without specified voltage or load so its voltage is different in 50, 60, 75, 120, 300, 600, 1kohm and so on...

If one work with audio 600ohm impedance system SDG2000X have solution.
Do not use default 50ohm Load setup, adjust it to 600ohm.
Now if you set 0dBm  level is 0dBu and you see  0.7746Vrms (1.095V pk) and if you set level for -10dBu your level is 0.2448Vrms (0.346Vpk or double Vp-p)

So as long as user work with  600 Ohm audio "standard" impedance(load)  and  have set 600 ohm load in SDG2000X menu  then dBu == dBm

Siglent or who ever can not add simply dBu if think it is just universally Voltage based to 0dBu 0.7746Vrms (roughly 2.190 Vpeak-peak) independent of load or this mysterious dB"unloaded" when it still in practice is loaded and generator do not have leveled or zero output impedance.
I do not know any serious audio equipment what have signal input without load. I have also not seen many cheap generators what have zero output impedance or leveled output. Perhaps they exist in world of audio. But example my normal audio amplifier do not even tell input impedance.
If user know his load is 4700 ohm he can set SDG for 4700 load and now he adjust 1V out he get 1V to this load. After then when he can use simple slide rule he know what is dBu. Or he use his slide rule and look how much voltage he need set for -5dBu and he set this voltage and all is ok... until he plug his output to input what have 1200 ohm load... now all is wrong until he tell this load value to generator and then set wanted level.
As far we do not have leveled output or zero(very low)  impedance output  we need know Load for set voltage independent of if we use dBV, dBv, dBu or V or what ever based to voltage.

[Messtechniker]

If one work with audio 600ohm impedance system SDG2000X have solution.
Do not use default 50ohm Load setup, adjust it to 600ohm.
Now if you set 0dBm level is 0dBu and you see  0.7746Vrms (1.095V pk) and if you set level for -10dBu your level is 0.2448Vrms (0.346Vpk or double Vp-p)

Thanks for reminding me of this which I should have known. While making the measurements using the SDG 2042X by brain was occupied with troubleshooting the difficult target. This well-broken R&S UPGR Psophometer. But all is well now.

When setting the SDG to 600 Ohms and 0.0 dB amplitude is off by +0.7 dB. Faking the load to 495 Ohms gives the correct output of 0.7746 V as measured with the equipment given below.
 Being off by +0.7 dB seems to me a bit much. Could any other SDG 2042X (or similar) owners verify this?

[rf-loop]

If one work with audio 600ohm impedance system SDG2000X have solution.
Do not use default 50ohm Load setup, adjust it to 600ohm.
Now if you set 0dBm level is 0dBu and you see  0.7746Vrms (1.095V pk) and if you set level for -10dBu your level is 0.2448Vrms (0.346Vpk or double Vp-p)

Thanks for reminding me of this which I should have known. While making the measurements using the SDG 2042X by brain was occupied with troubleshooting the difficult target. This well-broken R&S UPGR Psophometer. But all is well now.

When setting the SDG to 600 Ohms and 0.0 dB amplitude is off by +0.7 dB. Faking the load to 495 Ohms gives the correct output of 0.7746 V as measured with the equipment given below.
 Being off by +0.7 dB seems to me a bit much. Could any other SDG 2042X (or similar) owners verify this?

Bit high: Error is 0.7dB too high.
Data sheet tell +/- 0.3dB flatness with 50 Ohm system in 0 - 100MHz range and 2.5Vpp level @10kHz
Accuracy  +/- (1% +1mV) @10kHz Sine 0V offset
Internal output impedance 49.5 - 50.5 Ohm @10kHz Sine

Then output set for 0dBm (not 0dB) for 600ohm what need give 0.7746Vrms  but voltage is too high and you change load to 495ohm and then voltage level is 0,7746Vrms.   
When I try to calculate it looks like something is weird or least I can not get match this Load change... except if there is bug in SDG math or some kind of calibration issue  or some other thing is wrong.

Using 0dBm on 600Ohm system level is 0.7746 Vrms
If it is 0.7dB high it is 0.8395 Vrms  there is roughly 65mVrms difference. What all separate errors it include.
Next measurements may give more result and also there is used frequency what are used in specifications.

So please can you do these measurements.
Set generator first fully to factory defaults for avoid any "oops" mistakes..

1.
-Set Load Hi-Z and keep it until said other set value
-Set Sine and set 10 kHz. Set output level 0.775 Vrms  and keep until sais other value.
-Set/check DC offset 0 and check it do not have any residue, if have fine adjust for real Zero DC offset and keep this in all next.

-Measure open circuit voltage level Vrms (AC True Rms or AC+DC True Rms) Result =______  (default = 0.775 Vrms)
-Connect 600 ohm load and measure loaded voltage level Vrms, Result =______   (default = 0.7154 Vrms)
-Connect 100 ohm load and measure loaded voltage level Vrms, Result =______   (default = 0.5167 Vrms)

2.
-Set Load 50 Ohm and keep it
-Output level set  for 0.775 Vrms
-Measure Open circuit voltage level Vrms, Result =______   (default 1.550 Vrms)
-Connect 50 Ohm Load and measure loaded voltage level Vrms, Result =______  (default 0.775 Vrms)
-Set output level for 0dBm and measure loaded voltage level Vrms, Result =______  (default 0.2236 Vrms)
-Set output level for 6dBm and measure loaded voltage level Vrms, Result =______  (default 0.4462 Vrms)
-Set output level back for 0dBm
-Disconnect 50 ohm load and measure open circuit voltage level Vrms, Result =______  (default 0.4472 Vrms)

3.
-Set Load 600 Ohm and keep it
-Set Output level for 0.775 Vrms
-Measure open circuit voltage level Vrms, Result =______    (default 0.8396 Vrms)
-Connect 600 Ohm Load and measure loaded voltage level Vrms, Result =______  (default 0.775 Vrms)
-Set output level for 0dBm and measure loaded voltage level Vrms, Result =______ (default 0.775 Vrms (ideal 0.7746 Vrms))
-Set output level for 6dBm and measure loaded voltage level Vrms, Result =______  (default 1.546 Vrms)
-Disconnect 600 Ohm load and measure open circuit voltage level Vrms, Result =______  (default 1.675 Vrms)

Sorry if there is some inaccuracies (I hope not real mistakes) in values, I use slide rule.

[Messtechniker]

Did the measurements as given above. Got the expected values in each case.

When applying real load resistances to the generator I get the following:

Load setting on the generator = 600 Ohm
Real load / dB reading on the 34465A
600 Ohm / 0.00 dB
1 k Ohm / +0.2 dB
1.5 kOhm / + 0.43 dB
3 kOhm / +0.55 dB
5 k Ohm / + 0.6 dB
10 k Ohm / +0.66 dB
1 M Ohm and over / + 0,70 dB

[rf-loop]

So please can you do these measurements.
Set generator first fully to factory defaults for avoid any "oops" mistakes..

1.
-Set Load Hi-Z and keep it until said other set value
-Set Sine and set 10 kHz. Set output level 0.775 Vrms  and keep until sais other value.
-Set/check DC offset 0 and check it do not have any residue, if have fine adjust for real Zero DC offset and keep this in all next.

-Measure open circuit voltage level Vrms (AC True Rms or AC+DC True Rms) Result =______  (default = 0.775 Vrms)
-Connect 600 ohm load and measure loaded voltage level Vrms, Result =______   (default = 0.7154 Vrms)
-Connect 100 ohm load and measure loaded voltage level Vrms, Result =______   (default = 0.5167 Vrms)

2.
-Set Load 50 Ohm and keep it
-Output level set  for 0.775 Vrms
-Measure Open circuit voltage level Vrms, Result =______   (default 1.550 Vrms)
-Connect 50 Ohm Load and measure loaded voltage level Vrms, Result =______  (default 0.775 Vrms)
-Set output level for 0dBm and measure loaded voltage level Vrms, Result =______  (default 0.2236 Vrms)
-Set output level for 6dBm and measure loaded voltage level Vrms, Result =______  (default 0.4462 Vrms)
-Set output level back for 0dBm
-Disconnect 50 ohm load and measure open circuit voltage level Vrms, Result =______  (default 0.4472 Vrms)

3.
-Set Load 600 Ohm and keep it
-Set Output level for 0.775 Vrms
-Measure open circuit voltage level Vrms, Result =______    (default 0.8396 Vrms)
-Connect 600 Ohm Load and measure loaded voltage level Vrms, Result =______  (default 0.775 Vrms)
-Set output level for 0dBm and measure loaded voltage level Vrms, Result =______ (default 0.775 Vrms (ideal 0.7746 Vrms))
-Set output level for 6dBm and measure loaded voltage level Vrms, Result =______  (default 1.546 Vrms)
-Disconnect 600 Ohm load and measure open circuit voltage level Vrms, Result =______  (default 1.675 Vrms)

Did the measurements as given above. Got the expected values in each case.

So it works just right as designed.

When applying real load resistances to the generator I get the following:

Load setting on the generator = 600 Ohm
Real load / dB reading on the 34465A
600 Ohm / 0.00 dB
1 k Ohm / +0.2 dB
1.5 kOhm / + 0.43 dB
3 kOhm / +0.55 dB
5 k Ohm / + 0.6 dB
10 k Ohm / +0.66 dB
1 M Ohm and over / + 0,70 dB

"600 Ohm / 0.00 dB"  Just as it need be  when looks Voltage levels when all is ok.
Open load voltage  0.8396 Vrms is 0.7dB higher (dBu) higher than  600 Ohm loaded voltage 0dBu (0dBm 600 Ohm) what is 0.7746 Vrms. So it works ok and internal math is just ok.

When setting the SDG to 600 Ohms and 0.0 dB amplitude is off by +0.7 dB. Faking the load to 495 Ohms gives the correct output of 0.7746 V as measured with the equipment given below.
Being off by +0.7 dB seems to me a bit much. Could any other SDG 2042X (or similar) owners verify this?

So,  what was this all about 0.7dB error with 600 ohm and then 495 ohm Load what give correct output. Some mistake in measurement?

As said previously
With SDG  dBu == dBm IF real load impedance  is 600 ohm AND IF user have set SDG Load setting for 600 Ohm.
If real load impedance is then higher than 600 there is level error*) 0 - up to 0.7dB (your data also proof it works) + other errors as told in data sheet.
*) "error" is based to 50 Ohm internal impedance.

With 0dBm level voltage for 600 Ohm load is 0.775 Vrms (generator have only 1mV steps)
GND -- Generator(Z0)  -- 50 ohm -- OUT Terminal -- external Load 600 ohm -- GND  Total signal pathway have 650 Ohm so generator Z0 output need be 0.83958 Vrms.

Now if just change true load to 1,5k total is 1.55k then there is  0.8125Vrms over this 1.5k load and it is 0.415dBu and you measure 0.42dB(u).
But true power level is of course NOT 0.42dBm what display still show, because we have told 600ohm Load but true Load is 1.5k because dBm is power and now there is Load 1.5k so it is -3.564dBm !!
With these and with real life various load values in different cases there is BIG danger to go error.

So, if use SDG  dBm units here for set levels as dBu unit,  load set and true load both need be 600 Ohm. Only then dBm unit can use as dBu unit with SDG2000X.

Open load voltage 0.8396 Vrms is 0.7dB higher (dBu) higher than  600 Ohm loaded voltage 0dBu (0dBm 600 Ohm) what is 0.7746 Vrms. It works ok and internal math is just ok.

 

[mawyatt]

I can confirm that the SDG2042X AWG output does work as expected when understanding that the output impedance is always 50 ohms regardless of what the load impedance is set to in the Load Setting. The AWG always has a fixed 50 ohm output impedance, then the actual generator voltage at the generator source is:

VG = [(RG+RL)/RL]* Sqrt(RL*P), where P is the power, RL is load and RG is generator (50 ohms for SDG2042X). Reading an Open Circuit output is then reading VG, and reading a loaded output includes RG and is VG*(RL/(RL +RG), so with a setting of 50 ohms the OC is twice the loaded voltage.

For example with a 0dBm (0.001W) at 1KHz reference:

Set to 50 ohms Open Circuit =~ 0.447 Vrms (correct value)
100 ohms OC ~ 0.474 Vrms (correct value)
600 ohms OC ~ 0.839 Vrms (correct value)
1K ohm OC ~ 1.049 Vrms (correct value)
10K ohm OC ~ 3.177 Vrms (correct value)

These readings were taken with a new Keysight 34465A DMM.

Best,

Edit to correct typo.

[Messtechniker]

Thanks for getting me up to date.
Just wandering.
Do other generators work in the same way?

[mawyatt]

Don't know regarding how others work as this is the only AWG I have available at the moment. If the design decision is not to allow variable or settable generator output impedance then the approach Siglent has taken with a constant 50 ohms output and calculating the required voltage at the load to achieve a given power seems a good decision given the design constraint.

It can be confusing at first, especially when you think the unloaded output voltage should be twice the loaded and find this is only true at 50 ohm load, but then realize what's going on and it seems logical.

Anyway, these are just my thoughts on why this route was taken.

Best,

[radiolistener]

impedance setting is used just to display voltage for specific load. Actual output impedance is always 50 Ohm

[Blue]

Bricking alert!

My unit was running perfectly fine until did the following:

1) Firmware upgrade 22R5 => 23R3, after successful upgrade just continued to use and did following:
2) Used EasyWave to send 8pts wfm, played around with DDS/TrueArb setting etc. Turned unit off while custom wfm was loaded.

Next day unit now shows blank screen after logo. Controls non-responsive. Parameter button is lit. Not recognized as USB device. But LAN shows functional login screen. Do not know user/pass.

Since did 2 things first time (not used EW before) cannot be sure which activity bricked it. My first idea would be delete custom wfm. Maybe loading it at boot bricks it. But cannot get in....

Ordered online from siglent.eu quite a hassle sending it back etc... Since LAN is working maybe there is some trick to resurrect it? Can firmware be upgraded / downgraded over LAN? Reset procedure? Telnet user / pass?

I realize MrW0lf's message is 2 years old, but I'd like to share my somewhat similar bricking experience and solution.

A couple hours ago I bricked my SDG2042X (modified long ago to SDG2122X by using patched 23R7 firmware and modified XML file). Today I was trying to upload a waveform into the instrument by using low-level SCPI over TCP without needing any NI or Siglent software. I accidentally fumbled my code, resulting in a zero-length waveform stored in the instrument, and then I power-cycled the instrument to clear its stuck TCP state. Bricked! During power-up it displayed the logo for about 25 seconds, then several LED flash briefly, then the LCD goes blank forever.

I unbricked the instrument by connecting via telnet (thanks to the patched firmware), moved into /usr/bin/siglent/usr/usr, deleted my bogus zero-length waveform, power-cycled the instrument, and now it boots fine. Whew!

Maybe that will be helpful to someone else.

I liberated my SDG2042x with the telnet_SDG200x.ads trick and changing the configuration file. I have the lastest firmware 35R3B2 (as of march 2021) firmware installed.

Question Is this firmware also vulnerable to the bug/error described above? Could I brick the instrument?
Apparantly I can not telnet into root. Is there a solution allowing me to telnet into root in this latest firmware?