New 2ch pocket DSO+SG - Zeeweii DSO2512G

[Sham73]

https://www.eevblog.com/forum/testgear/new-2ch-pocket-dsosg-sigpeak-dso2512g/msg5083081/#msg5083081

I have firmware 1.3.0C. Is there an update 1.3.0C+ for it too?

[Sham73]

**Open user calibration function.
How to perform AC Gain calibration:
1. The oscilloscope measures the 2.5V 1Khz sin waveform. Observe the "PKPK" measurement item.
2. Open Menu-> Meas, then press the CH1CH2 button, and then long press the [mV] key to enter the AC Gain calibration mode.
3. The UP DOWN button is used to increase/decrease the CH1 Gain until the "PKPK" voltage is equal to or close to the voltage of the signal generator.
4. The LEFT RIGHT button is used to increase/decrease the CH2 Gain until the "PKPK" voltage is equal to or close to the voltage of the signal generator.
5. Press the OK button to exit and complete the calibration.

How to perform DC offset calibration:
1. The oscilloscope measures the DC power supply. Observe the "Mean" measurement item.
2. Open Menu-> Meas, then press the CH1CH2 button, and then long press the [V] key to enter the DC offset calibration mode.
3. The UP / DOWN button is used to increase/decrease the CH1 dc offset until the "Mean" voltage is equal to or close to the voltage of the multimeter.
4. The LEFT / RIGHT button is used to increase/decrease the CH2 dc offset until the "Mean" voltage is equal to or close to the voltage of the multimeter.
5. Press the OK button to exit and complete the calibration.
Different vertical sensitivities use different calibration parameters, so they need to be calibrated separately.


**add [ZOOM]
Long press the "s" key to turn on/off Zoom mode.
(Zoom is not supported when roll mode or cursor is on\
It is recommended to exit Zoom mode before shutting down to avoid measure item are cleared)

What sources do you use for AC and DC calibration?

[Aldo22]

What sources do you use for AC and DC calibration?

With what I had at hand.
I took my FY3224s and verified the voltage with the multimeter. This for all voltage ranges, but only at 1kHz.
Here is a photo of it: https://www.eevblog.com/forum/testgear/new-2ch-pocket-dsosg-sigpeak-dso2512g/msg5086450/#msg5086450

Today I might do it with my second scope.
But you shouldn't exaggerate, it's not a high precision device. 

[Sham73]

But you shouldn't exaggerate, it's not a high precision device. 

Do you mean FY3224s... or DSO2512G?

[Aldo22]

But you shouldn't exaggerate, it's not a high precision device. 

Do you mean FY3224s... or DSO2512G?

Both of course. 
Both are pretty much the cheapest usable representatives of their kind.
FY3224s has quite good precision (frequency response) up to 10MHz / 10V, but is not very accurate, i.e. the multimeter shows slightly different values in certain voltage ranges from what is set on the FY3224s.
Normal oscilloscopes are rarely very accurate. 2%-5% voltage is normal.
That's OK, just don't overdo the calibration, it won't be like a multimeter.

https://en.wikipedia.org/wiki/Accuracy_and_precision

[tunk]

FY3224s has quite good precision (frequency response) up to 10MHz / 10V, but is not very accurate, i.e. the multimeter shows slightly different values in certain voltage ranges from what is set on the FY3224s.

It may be caused by the multimeter - multimeters also have a frequency range.

[Aldo22]

It may be caused by the multimeter - multimeters also have a frequency range.

Absolutely, that's why I only compared the different voltage ranges at 1kHz and DC.
At 1kHz, the multimeter is quite accurate.
Then you can increase the frequency and look at the frequency response ("hobby accuracy" of course...)

[Sham73]

That's OK, just don't overdo the calibration, it won't be like a multimeter.

For calibration, I need a more or less accurate laboratory power supply and a functional signal generator, which I don’t have.

[Aldo22]

For calibration, I need a more or less accurate laboratory power supply and a functional signal generator, which I don’t have.

It's not really necessary.
You have "Auto cal" in the Aux menu.

[chemary]

That's OK, just don't overdo the calibration, it won't be like a multimeter.

For calibration, I need a more or less accurate laboratory power supply and a functional signal generator, which I don’t have.

If you don't want to spend much, I purchased a cheap device like this one https://www.aliexpress.com/item/1005006786894152.html it comes with a hand written paper with the real measured values with good equipment and also states the date and temperature when they were done, it can be used to know how good are the measures of your equipment.

[Aldo22]

That's OK, just don't overdo the calibration, it won't be like a multimeter.

For calibration, I need a more or less accurate laboratory power supply and a functional signal generator, which I don’t have.

If you don't want to spend much, I purchased a cheap device like this one https://www.aliexpress.com/item/1005006786894152.html it comes with a hand written paper with the real measured values with good equipment and also states the date and temperature when they were done, it can be used to know how good are the measures of your equipment.

That's certainly nice, but only DC (afaics) and you don't really need that kind of accuracy for the scope.
An average multimeter is perfectly adequate as a comparison.
The scope only has to display approximately the same as the multimeter. So not exactly 1.0000V but e.g. with a battery 1.5xV or 9.xxV

But Autocal is also sufficient imo.

By the way, an FY3224s also has a DC mode and you can output -10V to +10V DC. If you compare this with a multimeter, it should be accurate enough as a reference for the scope.
Of course it can do sine, square etc. anyway.

[Sham73]

That's OK, just don't overdo the calibration, it won't be like a multimeter.

For calibration, I need a more or less accurate laboratory power supply and a functional signal generator, which I don’t have.

If you don't want to spend much, I purchased a cheap device like this one https://www.aliexpress.com/item/1005006786894152.html it comes with a hand written paper with the real measured values with good equipment and also states the date and temperature when they were done, it can be used to know how good are the measures of your equipment.

I have such.  I purchased it to determine the accuracy of my Owon B41T+ multimeter.  It only has four values ​​from 2.5 to 10 VDC, so I didn't mention it.