Author Topic: Rigol's New Function Generator and DMM: DG800Pro / 900Pro / DM858  (Read 11699 times)

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Online csuhi17

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Naturally.
These three musketeers are just that kind. :-+
I don't mind the 1-minute switch-on time, I let it warm up for a couple of 10 minutes. If I start doing something and use it several times, I don't turn it on and off...

This is also true for the DM858.
If I need to measure something quickly, my Owon HDS scope meter is there for that.
Or, according to my new habit, I use the Multimeter part of the Owon SPM, at my desk.  :palm:

I'm not going to throw away my Fy6800 either, it's more than adequate, if I need a more accurate and complex waveform, I'll turn on Rigol and while I wait, I'll occupy myself with something until then.

I can never understand why anyone would be bothered by the 1 minute power-on time with these devices. The minimum heating time is also written on more serious instruments.
Or does it have no practical use, and I just operated my devices unnecessarily?
 

Online csuhi17

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I actually wonder what's below the metal shield. It seems small, Rigol doesn't do DMM chipsets so it will be someone else's chip there.

There you go. :palm:
At first I thought it was soldered on, but luckily it wasn't.  :phew:
 
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Online shapirus

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I wonder where the operating system is stored. What's under that secondary board that's installed in what looks similar to a laptop memory module slot?
 

Offline TurboTom

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Thanks for posting, now I'm seriously considering getting a DG821Pro instead of the SDG2042X (to be hacked into SDG2122X). But the boot time seems to be long enough to be annoying.

I'm pretty sure the user interface of the DG800/900 Pro is much more comfortable to use than the SDG2000X counterpart. The decent screen size with touch screen functionality ironed in right from the start is a big plus in contrary to the SDG2kX /6kX instruments that had their firmware origin in the SDG1k series w/o touch screen support...

But one thing that would really put me off getting Rigol's "Pro" series AWG is the use of a hybrid module as the channel output amps. They may be designed pretty well and beefy but there's always a hatch that "Murphy" slips through and the pamp may be damaged by mishaps... If the "standard" TI THS3091 / 3095 series current-feedback OPAMPs are used as drivers, there's at least a chance of a DIY hardware repair (calibation/adjustment to meet specs again may be a different story), but Rigol's output driver modules will probably be and stay pretty much unobtainium. It's even questionable if Rigol themselves will replace individual chips/hybrids instead of rather replacing the whole mainboard and swapping the SIMM style CPU module. If this would be substantially less expensive than the purchase of a new DG821Pro has yet to be found out.

One more thought on the DG800 -> DG900 series upgrade: With the "non-Pro-versions" the situation was pretty similar -- that is, the hardware is identical. Yet, we had to find out that the calibration isn't done to the full DG900 specs which results in an output level drop of ~2dB between 70 and 100MHz. Nevertheless, the liberated instrument is pretty well usable, but don't expect the situation to be much different with the "Pro" series. Rather keep your expectations low than getting disappointed afterwards...

Good luck!  ;D
 

Offline zrq

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Re: Rigol's New Function Generator and DMM: DG800Pro / 900Pro / DM858
« Reply #104 on: March 26, 2024, 09:06:47 pm »
I would rather treat it as a consumer electronic product as it cost a fraction of an iPhone. If I blown up the front end by reverse power, then I buy a new one.
Also considering how fast the digital electronics are advancing today, hopefully by that time I can get one with even better specs. I was dreaming for but couldn't afford a second-hand Agilent 33250A when I was in high school, but today, meh...

Now the question is should I get a DG800Pro for hacking or a SDG2000X. I have the equipment to calibrate the frequency response if necessary. SDG2000X is a bit old now, I don't know if Siglent is going to release a newer model.
« Last Edit: March 26, 2024, 09:32:18 pm by zrq »
 

Offline thm_w

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I wonder where the operating system is stored. What's under that secondary board that's installed in what looks similar to a laptop memory module slot?

Everything is on that module, A40i-h SOM. RAM, CPU, flash. Similar to this sort of board: https://www.armdesigner.com/CM-A40i/
I don't know whats under though.

edit: DG821 pro is $333 - $40 coupon = $293 USD, https://www.aliexpress.com/item/1005006749594531.html
Just beware as it is a new store so there is a chance it won't show up and you'll need to get a refund. But looking at their reviews they've sold a few items.
« Last Edit: March 26, 2024, 11:34:23 pm by thm_w »
Profile -> Modify profile -> Look and Layout ->  Don't show users' signatures
 

Offline gbix

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Re: Rigol's New Function Generator and DMM: DG800Pro / 900Pro / DM858
« Reply #106 on: March 26, 2024, 10:19:55 pm »
i think DG800Pro :) as DG900Pro and calibrate it
 
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Offline PELLTopic starter

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Re: Rigol's New Function Generator and DMM: DG800Pro / 900Pro / DM858
« Reply #107 on: Yesterday at 01:02:14 am »
Thanks @csuhi17 for teardown DM858 :-+

I am pretty sure the chip is HY3131 or HY3130, which is not good to see a handheld chip in a "Desktop Grade" product. :palm:
« Last Edit: Yesterday at 01:06:34 am by PELL »
 
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Offline PELLTopic starter

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But one thing that would really put me off getting Rigol's "Pro" series AWG is the use of a hybrid module as the channel output amps. They may be designed pretty well and beefy but there's always a hatch that "Murphy" slips through and the pamp may be damaged by mishaps...

Yes, that is something definitely considerable when using it.

When you output at a very low amplitude, the wave comes directly from the DAC.

From what I can tell now, the "Custom ASIC" actually includes two dies, and you can see it in my teardown photo,  one is their own and the other one is some off-the-shell part.
« Last Edit: Yesterday at 01:07:30 am by PELL »
 
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Offline TurboTom

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Re: Rigol's New Function Generator and DMM: DG800Pro / 900Pro / DM858
« Reply #109 on: Yesterday at 02:09:52 am »
The high-speed DACs used in these AWGs usually have differential current outputs, thus keeping voltage swing as small as possible. This signal is fed through the reconstruction filter and then to a trans-impedance amplifier to turn it into a single-ended voltage signal. This voltage signal is resistively added to an offset signal from an auxiliary DAC, amplified by a large output swing OPAMP. The individual resistors of this resistive adder are chosen to provide an impedance of 50 Ohms. As you mentioned, this signal is used directly or routed through a set of attenuators for low-level outputs. If a higher output level (or offset) is required, this whole signal is amplified typically by a THS3091 high-speed current feedback opamp. In most designs, there are three or four attenuator stages and the amplifier available to be routed via relays into the signal path.

Hence, a whole bunch of calibration constants, covering all amp/attenuator configuration combinations at several frequency points and offset conditions are required to fully tame such a complex contraption. Depending on the operational mode (i.e. amplitude or frequency sweeps, during which no attenuator switching is acceptable), even further calibraion points may be required. Fact is that on this forum, the calbration adjustment procedure for the legacy DG800/900 has not (yet) been figured out completely. Siglent's AWGs require some Python scripts to perform adjustments and I haven't seen any copies of those anywhere "in the wild". So a complete DIY adjustment looks pretty impossible, and I'ld assume it will be the same with the DG800/900 Pro AWGs.

It's well possible that, provided the right folks have a look into this problem, a solution can be found. But that will be a hell lot of work, and success cannot be taken for sure. Sorry for my doubtful attitude in this case, but as we've got a saying "A pessimist is an optimist with experience..."  ;)

Cheers  :)
« Last Edit: Yesterday at 02:13:49 am by TurboTom »
 
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Offline gbix

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Re: Rigol's New Function Generator and DMM: DG800Pro / 900Pro / DM858
« Reply #110 on: Yesterday at 02:32:48 am »
All DG800pro don't have calibration on high freq, but all DG900pro have full calibration
Commands for calibration I found and soon I documents it.
High freq table have 71 points to calibrate at double64 precision
Low freq is below 200khz and also have 78 points
« Last Edit: Yesterday at 01:06:06 pm by gbix »
 
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Online csuhi17

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Re: Rigol's New Function Generator and DMM: DG800Pro / 900Pro / DM858
« Reply #111 on: Yesterday at 05:37:45 am »
I took out the DM858 card, you have to be careful, because there are small parts next to the catch plate, they are easy to break off.
 
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Offline gbix

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Re: Rigol's New Function Generator and DMM: DG800Pro / 900Pro / DM858
« Reply #112 on: Yesterday at 10:25:51 pm »
I would rather treat it as a consumer electronic product as it cost a fraction of an iPhone. If I blown up the front end by reverse power, then I buy a new one.
Also considering how fast the digital electronics are advancing today, hopefully by that time I can get one with even better specs. I was dreaming for but couldn't afford a second-hand Agilent 33250A when I was in high school, but today, meh...

Now the question is should I get a DG800Pro for hacking or a SDG2000X. I have the equipment to calibrate the frequency response if necessary. SDG2000X is a bit old now, I don't know if Siglent is going to release a newer model.

What equipment do you have for calibration or what is enough to calibrate it?
 
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Offline zrq

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I was thinking if what I need is amplitude calibration at higher frequencies, I have access to leveled spectrum analyzers and power meters.
 


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