The Siglent SDG2042X Thread

[gmb42]

Oh dear......your scope. 

Why denigrate another users choice of equipment, especially when you're trying to persuade him to buy equipment from the manufacturer you resell for?

As the screen shot shows 3 channels are required for this application.

The cheapest Siglent 4 channel I can find is the SDS2104x at $1285.

The user's Rigol DS10??Z is available in DS1054Z form for $399 and can be unlocked to approximately the same bandwidth as the Siglent.

I leave it up to others to decide if the Siglent is worth more than 3 times as much in order to meet their requirements and the depths of their pockets.

[tautech]

Oh dear......your scope. 

Why denigrate another users choice of equipment, especially when you're trying to persuade him to buy equipment from the manufacturer you resell for?

Said in jest, has nobody a sense of humor anymore ? 

Furthermore Plasmateur wants some features added to equipment he already has, or did you miss that while you had your blood pressure up.....no apology necessary, we all make mistakes. 

[diodak]

Has anyone tried the auto calibration?
Utilit->System->System Inf->Enter Password “123654”->SelfCal

[MrW0lf]

It looks like this machine could do that with the correct firmware, that is.

Just little workaround suggestion... if I understood application: Just buy second unit.
2xSDG2042X is about best value I ever spent on any new lab tech. 4 channel clock/phase lock zero jitter (detectable with given scope):
https://www.eevblog.com/forum/testgear/the-siglent-sdg2042x-thread/msg1082659/#msg1082659
Only burst mode possible, but burst can be pretty long so mostly ok. I used it for 4x sine waves but
could be anything.

[Tjuurko]

Once I have set an amplitude I would like to be able to change the units without changing the actual amplitude, eg V RMS to V Pk to Pk or dBm to mV RMS.

Such a feature is easy to implement for sine wave only.

[nctnico]

Has anyone some comments about the arbitrary waveform capabilities? I may get a project where the 8Mpts AWG functionality in the SDG2000X series could prove useful.

[AndyC247]

I have my SDG2042X configured to restore the last used settings on power up. I had set it to output a 7.1MHz sinewave at 0 dBm. When I next turned it on it restored the 7.1MHz but instead of displaying 0 dBm it displayed the equivalent in mV RMS. So it doesn't appear to store the units that the output level was entered in?

Regards,
Andrew

[tautech]

I have my SDG2042X configured to restore the last used settings on power up. I had set it to output a 7.1MHz sinewave at 0 dBm. When I next turned it on it restored the 7.1MHz but instead of displaying 0 dBm it displayed the equivalent in mV RMS. So it doesn't appear to store the units that the output level was entered in?

Regards,
Andrew

Please check your FW version, the latest being 22R5
http://www.siglentamerica.com/gjjrj-xq.aspx?id=4960&tid=15

In the change log there are 2 mentions of similar to what you describe:
e) Instrument Powers Up With Wrong Waveforms
h) Can not save the last state after the update

I'll check one I have in stock before I report your issue to Tech support unless someone else can confirm.

[AndyC247]

I confirm I have the latest firmware 22R5

Andrew

[tautech]

I confirm I have the latest firmware 22R5

Andrew

Some small feedback on your issue:
The Amplitude unit change issue is a known bug and they are working on it.

But something I didn't know and maybe of some help:
The LAST function can take up to one minute to work – the system only scans that key function that often.

[bson]

Is there a way to make the SDG2000X output DC?  It doesn't seem to like being set to 0Hz, or a 0V amplitude on top of a DC offset.  Sometimes it's really handy to have a programmable voltage source that's more accurate and precise than a PSU.

I'm looking to measure a pile of LDR devices (32SR2) - these optoisolators consist of an LED on one side and a photoresistor on the other, embedded in a package. Drive the LED and the resistance drops.  I plan to put these in a voltage-controlled test fixture that accepts 0-3.3V and drives the LED side with a known current response.  I want to drive the fixture from the SDG2000X with a programmable voltage, using its LXI ethernet interface.  The input impedance is high, so it's not like the FG has to supply more than a few mA, maybe 10mA, and that should be no problem.

I could of course use a PSU and then measure its actual output voltage, but then I won't get device measurements at the same points.

[Hergen Lehmann]

Is there a way to make the SDG2000X output DC?  It doesn't seem to like being set to 0Hz, or a 0V amplitude on top of a DC offset.  Sometimes it's really handy to have a programmable voltage source that's more accurate and precise than a PSU.

There is a waveform called "DC" on the second page of the waveform menu.
Accuracy is not that outstanding, though. On my device, i get ~0.3% error on the selected offset voltage. A good programmable PSU might give better results.

[bson]

Oh, didn't see that!  Excellent!

Doesn't seem so bad to me. 

Set it to 357.9mV and my 34465A reads 0.357590V, at 100PLC and nulled (short).  That's an error of about 0.04%.

It seems the error varies, and for some values I get around 0.01%.  This also doesn't seem random but quite reproducible, so I can pick test voltages I know have good accuracy... :p

(It's probably a DAC word size issue.)

[tautech]

Oh, didn't see that!  Excellent!

Doesn't seem so bad to me. 

Set it to 357.9mV and my 34465A reads 0.357590V, at 100PLC and nulled (short).  That's an error of about 0.04%.

It seems the error varies, and for some values I get around 0.01%.  This also doesn't seem random but quite reproducible, so I can pick test voltages I know have good accuracy... :p

(It's probably a DAC word size issue.)

FYI
All Siglent AWG's have a DC (waveform) output mode and it can be used to power small projects if needed.
The source impedance is 50 so the current supplied is limited.
All models except the SDG5000 series have BNC shells common'd with mains ground so the negative of the DC supply will be mains ground referenced.

[Plasmateur]

Oh dear......your scope. 

Why denigrate another users choice of equipment, especially when you're trying to persuade him to buy equipment from the manufacturer you resell for?

Said in jest, has nobody a sense of humor anymore ? 

Furthermore Plasmateur wants some features added to equipment he already has, or did you miss that while you had your blood pressure up.....no apology necessary, we all make mistakes. 

I thought it was funny, no harm no foul.

And technically the SDG2042X has three outputs for my application if the aux out is simply used as a TTL gated signal while the front outputs are used as AFG's.

As for needed the AUX out to be variable. Not needed. 5V TTL gate would be great.

Would be great if all these could be triggered from the same software trigger.

[pherdie]

Is there any method to change the output reading from peak to peak volts to something really useful like dbm or rms (available on the Rigols). Sure would make life more pleasant for me as opposed to doing constant conversions. It appears Siglent did it for the units they made for Teledyne so they must have the code already written.

Did I miss a menu item?

[tautech]

Is there any method to change the output reading from peak to peak volts to something really useful like dbm or rms (available on the Rigols). Sure would make life more pleasant for me as opposed to doing constant conversions. It appears Siglent did it for the units they made for Teledyne so they must have the code already written.

Did I miss a menu item?

I hunted this out recently in another thread somewhere.
IIRC dBm units are only available in the 50 impedance output setting. You can change the output impedance in the Utility menu.

[MrW0lf]

You can change the output impedance in the Utility menu.

...or long-press CH* ON|OFF button.
Otherwise I have annoyance with same stuff others report when set to dBm and wander around in other screens it has forgot the unit and converted to volts equivalent

[rf-loop]

You can change the output impedance in the Utility menu.

I know you know but for avoid  confusion...

This setting is not for  set output impedance, it is only for tell to equipment what is connected load impedance, for display right level value (if true load match with user made setup)!
Output impedance is always 50ohm. In all cases.

[MrW0lf]

I know you know but for avoid  confusion...

Quite confusing indeed. I never actually analyzed this, if set to 50ohm always have 50ohm termination etc. Now suppose one does not have termination. It shows wrong voltage then. Can claim user error etc but it is not good GUI practice to display only imaginary value, which cannot be guaranteed and depends on what user does with output. Is it like this on all signal gens?
Maybe there should be grayed out "Unload ampl." or something as reminder what is actually going on?

[tautech]

I know you know but for avoid  confusion...

Quite confusing indeed. I never actually analyzed this, if set to 50ohm always have 50ohm termination etc. Now suppose one does not have termination. It shows wrong voltage then. Can claim user error etc but it is not good GUI practice to display only imaginary value, which cannot be guaranteed and depends on what user does with output. Is it like this on all signal gens?
Maybe there should be grayed out "Unload ampl." or something as reminder what is actually going on?

Know your instrument  and how to properly use it. 

Set the output to try match the load. Simple IMO.

[nctnico]

I know you know but for avoid  confusion...

Quite confusing indeed. I never actually analyzed this, if set to 50ohm always have 50ohm termination etc. Now suppose one does not have termination. It shows wrong voltage then. Can claim user error etc but it is not good GUI practice to display only imaginary value, which cannot be guaranteed and depends on what user does with output. Is it like this on all signal gens?

Yes it is on all general purpose signal generators. The 50 Ohm output resistor also limits the short circuit current.

[MrW0lf]

Know your instrument  and how to properly use it. 

I AM using it properly. Just bit outsider to "RF conventions", not outsider to good GUI practices to save user from trouble. System I develop involves money transactions... Numbers gotta stick to reality, saying RTFM little help if "owned" customer shows up

Edit: Looked around sig. gen photos. Indeed seems convention not display 50ohm unloaded voltage. Can understand why convention because unloaded "real" RF amplifier may mean broken amplifier. Low freq sig gen more grey area, would still display "unloaded" voltage somewhere just in case if spare screen room. But with SDG2000X seems no room.

[tautech]

I'll post some screenshots for better clarity at 1M and 50 output settings...

Screenshots as promised
SDS1102X DSO
SDG1062X (same UI as 2042X and very similar specs.)
Pulse for better indications of current loadings when properly terminated.
Ch 2: Tek P6021 AC current probe. (values seen may not be correct (attenuation) but waveform is indicative of what's happening)

Shot 1 with only 50 scope internal termination.
Waveform is identical with either 50 or 1M sig gen source impedance. Only the sig gen displays a difference depending on the source impedance selected.



Next is entirely different, the source is always 50 from the sig gen (explained earlier) but the termination impedance matters.



Tiny current spikes can be seen on rising and falling edges....clear on the display but not so in the screenshots.

[pherdie]

With egg on my face I answer my own question.

Yes, output can be designated in RMS or dbm as opposed to peak to peak, but only when the output load is set for 50 Ohms.

I found this quite by accident drilling through menus. It was not found in the pdf version of the operations manual using a pdf generated search.

Is there any method to change the output reading from peak to peak volts to something really useful like dbm or rms (available on the Rigols). Sure would make life more pleasant for me as opposed to doing constant conversions. It appears Siglent did it for the units they made for Teledyne so they must have the code already written.

Did I miss a menu item?/quote]