X10 Probes and some strange behaviour around the 2,5,10v DIV

I have adapted a set of more sustantial probes designed for a standard scope. I am not sure yet how the different input resistance affects this. An one know if I have to add resistance to the probe, or is Nano going to be accurate with a standard X10 (9M between proe and ground)

Noticed something funny that I haven’t worked out… Here are some scanns at X10…

Notice the last image. When I move up to a 2V/DIV scale, the waveform disapears…

It comes back at 20V upwards… Is this a software issue or is it part of the workings of a digital scope that I am not understanding?

The different probes have different impedance, and when you change the probes , you need to change the compensation capacitorfor of each input channel . we have modify the compensation capacitorfor the Probes we supplied .

you use the X10 probes , the impedance is far different from ours ,and the mensuration is not accurate.you need to modify compensation capacitorfor to right value for your probes.

Is this internal to the DSO?

The probe I have used does use an adjustable compensation capacitor. I have been able to adjust it to get a square wave at 1khz…

This is normally sufficient on an analogue scope. I realise that the input impedance on the DSO is around 540K rather than 1M. Is this going to through the readings?

I have been probing about a bit more and the results are worrying… I am hoping that there is some way that this can be fixed.

I have measured the voltage of a switch mode power supply and I am still confused. Prior to this set of tests the probes adjustment capacitor was calibrated against a square wave.

First of all at 1v/div or lower, a 24v Power supply gives a reading of 7.6v. This is not a major suprise, I am guessing this is the max limit of this particular scale.

At 20v/div or higher I get an exact 24v reading, this is great, the power supply is hardly used and has clearly been calibrated well at the factory. I get the same reading with my multimeter. I was pleased with this result as it shows that the scope is capable of reading higher voltages accurately.

I am unsure as to why the 2v,5v and 10v are not giving readings…

I understand this, but I am suprised I get no reading at all. Looking at the schematic, I notice that the HC4051 works as a voltage divider? I can see that the waveform may be distorted by incorrect capacitance, but I dont see how this mechanism creates a zero reading?

I also had a look at the 1x probe and I am seeing some other issues with measurements…

Using the 1kz test signal on the DSO Nano corner with either the supplied probes or my own modified probes I get identical results (good news again)

However I am noticing different measurements depending on the v/div range used.

10v/div = 2.00 v avg
5v/div = 2.00 v avg
2v/div = 2.16 v avg
1v/div = 2.04 v avg
0.5v/div= 2.04 v avg
0.2v/div=2.04 v avg
below 0.2v/div = 384mv ie no reading. =

The 2v/div figure stands out compared to the other readings?

At the end of the day, modifying the 10x probe to work with the nano I would still say is worthwhile. Results are looking consistent between the 1x settings of the modded probe and the flimsy supplied items.

At 10x, obviously the 2v, 5v and 10v/div are not working which is pretty limiting.

But the other waveforms are there. 10x probes offer usually better results looking at a square wave, with an adjusted cap, the waves are near square, on a 1x probe are more consistent. If there is something that can be done to fix the missing div ranges it would be preferable…

Sorry, we were too busy last week for a timely response, will get back to this soon!

Thanks for testing it out! We are still working to complete it. X10 function might not be well supported for mass production in current design, however we will prepare a guide as advanced usage.

what signal source did you ues for testing this ? the 1KHz 5V square wave is too high level for the 0.1V/div , and is too low for the X10 div .

So have you tested some singal that more thant 20V for X10 div ?

Every channels include every X10 channels have its input range.