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Siglent SDG1032 as bad as rigol DG812?
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eTobey:

--- Quote from: TurboTom on May 19, 2024, 03:38:33 pm ---If you want to be sure that you won't overload your digital circuitry's input (Microprocessor?), why don't you set up a special test lead with a unidirectional protection diode installed in the connector closest to the DUT?


--- End quote ---

Yes i do want to make sure. Seems like i have to make such contraption, or spend a few figures more for a gen.

While trying and changing settings a lot, i do not really consider to get into a habit of checking the signal everytime. A contraption, that guards it well, no matter what, would be my choice.

Since the storing of the settings also does not work in all cases, i will not trust this device anyway.
2N3055:

--- Quote from: eTobey on May 19, 2024, 05:22:10 pm ---
--- Quote from: rf-loop on May 19, 2024, 04:52:32 pm ---
--- Quote from: eTobey on May 19, 2024, 03:00:43 pm ---
--- Quote from: rf-loop on May 19, 2024, 02:04:22 pm ---
--- Quote from: eTobey on May 19, 2024, 01:28:27 pm ---
--- Quote from: rf-loop on May 19, 2024, 12:36:28 pm ---But naturally my predictable rest of lifetime is not enough for test every possible setup combinations even once per setup.  ;)

--- End quote ---

If you would choose  a 100mHz square, and a 99% duty, you are more likely to hit that high level right at the beginning of the rest of your life.

On that picture it looks like you hit that low level...  ::)

--- End quote ---

That one magpie's nest type of signal connection that you recently brought up when you criticized the generator's frequency response. I will say one more and one last time. Most of the problems you'll encounter with oscilloscopes or generators are between them and the chair you sit. Next time I might say it less nicely.

Here is 100mHz and 99% Duty. And again hard PowOFF.
And yes, signal is 20Vpp and other is generator 10V DC out (also for trig)


--- End quote ---

If you set up values, that are far away from those that showed the issue, and want to compare, you also have a problem between the chair and the screen.

--- End quote ---

|O YOU ask'd this (if you remember)! And you get it.
And it still didn't show the problem you so desperately hoped for.

--- End quote ---

Of course it did not mean those values that i told you.  |O

I talked about spikes that went up to ~5V but you already set a level of 10V!  :palm:
Are you trying to hide the issue, or are you  trying to make me look bad?

--- End quote ---


He already did..

https://www.eevblog.com/forum/testgear/siglent-sdg1032-as-bad-as-rigol-dg812/msg5505127/#msg5505127
eTobey:

--- Quote from: 2N3055 on May 19, 2024, 05:34:21 pm ---He already did..

https://www.eevblog.com/forum/testgear/siglent-sdg1032-as-bad-as-rigol-dg812/msg5505127/#msg5505127

--- End quote ---
Dude, thats the wrong level, and the wrong time on the signal, i tried to tell you, but it didnt work...  :palm:
nctnico:

--- Quote from: eTobey on May 19, 2024, 05:22:10 pm ---
--- Quote from: rf-loop on May 19, 2024, 04:52:32 pm ---
--- Quote from: eTobey on May 19, 2024, 03:00:43 pm ---
--- Quote from: rf-loop on May 19, 2024, 02:04:22 pm ---
--- Quote from: eTobey on May 19, 2024, 01:28:27 pm ---
--- Quote from: rf-loop on May 19, 2024, 12:36:28 pm ---But naturally my predictable rest of lifetime is not enough for test every possible setup combinations even once per setup.  ;)

--- End quote ---

If you would choose  a 100mHz square, and a 99% duty, you are more likely to hit that high level right at the beginning of the rest of your life.

On that picture it looks like you hit that low level...  ::)

--- End quote ---

That one magpie's nest type of signal connection that you recently brought up when you criticized the generator's frequency response. I will say one more and one last time. Most of the problems you'll encounter with oscilloscopes or generators are between them and the chair you sit. Next time I might say it less nicely.

Here is 100mHz and 99% Duty. And again hard PowOFF.
And yes, signal is 20Vpp and other is generator 10V DC out (also for trig)


--- End quote ---

If you set up values, that are far away from those that showed the issue, and want to compare, you also have a problem between the chair and the screen.

--- End quote ---

|O YOU ask'd this (if you remember)! And you get it.
And it still didn't show the problem you so desperately hoped for.

--- End quote ---

Of course it did not mean those values that i told you.  |O

I talked about spikes that went up to ~5V but you already set a level of 10V!  :palm:
Are you trying to hide the issue, or are you  trying to make me look bad?

--- End quote ---
You make a good point here. When the generator is set to maximum output level, the output value is very unlikely to overshoot in the same way you and mortymore have shown. However, with a lower output level, the generator could overshoot when a mains interruption occurs. IOW: rf-loop should test with the same levels you and Mortymore have used. His screendump in the other thread does already show some negative undershoot.
Njk:
Gentlemen, you're right, of course. It may not be strictly related to any real use case. End of discussion?

But I would like to say that the screenshots make me slightly concerned about the instrument's reliability because the voltages are dropping too soon. Perhaps I'm missing something, but with DG811, the process takes an order of magnitude time longer (see the image below). Similar signals, the yellow trace shows the DC waveform which is used to trigger the scope and the other trace is for the same 500 Hz square wave signal. There are almost 11 ms between the first sign of power problem in the left and the last falling edge in the right part of the screen. Both the channels are loaded with 50 Ohm pass-throug terminators. Nevertheless, the yellow line is horizontal, the voltage is not dropping. While on the screenshots above, despite the DC channel is not loaded, the voltage starts gradually decaying in less than 1 ms after the power off event. If enough energy remains inside?

It seems in DG811 the power failure signal is generated well in advance, likely using the information from the primary side of the PS (as it should be done). What if Rigol is more used to design an instrument-grade PSUs in-house (whatever it costs), while it's natural for Siglent to outsource that work to contractors? That also explains why the problem can be seen not with every instrument, as it depends on exact model of the general-purpose PSU, which may vary from batch to batch.

The timing may be directly related to the reliability because the device is controlled by application processor. Typically, a chip like that uses several power voltages and the power on and off sequences are not up to the user. The sequences are stipulated by the chip vendor and must be obeyed. To make it easier to use the chip, the vendor typically provides an auxiliary chip (PMIC) that performs the sequencing automatically. Anyway, for that processor, the sequence takes tens of milliseconds, IIRC.

So on power failure notification, the processor have to gracefully finish with all the business logic and with all the housekeeping tasks like bad block re-allocation, etc., then, optionally, to disable as much peripherals as possible, and finally to instruct the PMIC to start with the power off sequence. That requires reservation of enough energy for PMIC. Otherwise, all the power voltages will be abruptly interrupted, violating the prescribed sequence. The vendor does not qualify the processor for such abnormal cases. Nobody knows what will happen. Perhaps nothing, but it's actually a Russian roulette.
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