Hacking the Rigol DHO800/900 Scope

[Fungus]

Somebody said the file got twice as big.

Maybe the 904 had a separate calibration file and this is the two files joined together to make one universal file.

[Silver_Is_Money]

Has anyone tried upgrade hacking the 802 yet?

[AndyBig]

Somebody said the file got twice as big.

Maybe the 904 had a separate calibration file and this is the two files joined together to make one universal file.

It became larger in the firmware update 01/00/02 for all models. It now has three times as many records, but the records themselves have become smaller and contain fewer values.
In addition, as far as I understand, in firmware 00.01.01 and earlier, the smaller file was also the same for all models; there was no separate file for 9xx. Although I could be wrong, because... I don't have the original .GEL file pulled from the 9xx model oscilloscope

[AndyBig]

By the way, I updated my program to read the calibration file cal_vertical.hex.

 calhex_read_1.1.zip (216.22 kB - downloaded 49 times.)

Now the program displays the calibration date and time (I found where they are stored in the file). Additionally, I added two options:
-o - inserts into the .csv file the offset for each entry relative to the beginning of the file in hexadecimal.
-O is the same as -o, but in decimal format.
This is done so that it is easy to find the entry of interest from the .csv in the .hex file.

[Randy222]

Maybe the new cal file was "digitized", meaning used some sort of actual stepping gear to calibrate the hardware, where before perhaps just linear interpolation between a few test points? 

[AndyBig]

Maybe the new cal file was "digitized", meaning used some sort of actual stepping gear to calibrate the hardware, where before perhaps just linear interpolation between a few test points? 

Unclear. If the calibration proceeds in steps and for each step its own coefficient is created in the calibration file (as I imagined before), then why does changing just one coefficient in the calibration file immediately affect all channels and many steps of the vertical scale? What are the other numbers in each entry next to the odds for (their value ranges from 0 to 3)? Perhaps these are the modes of input amplifiers/attenuators? For now there are only unanswered questions
If all this were understood, then it would be possible to manually refine the channel calibration more carefully than is done in automatic mode. Although, in principle, automatic calibration gives a satisfactory result, although not ideal.

[AndyBig]

I experimented with the supply voltage of the oscilloscope by connecting it to a laboratory power supply. The oscillograph works normally at a voltage from 9 to 16.8 volts, I was afraid to give more, not knowing what circuit it has at the power input. But since it is normally powered by 15 volts on its native power supply, it means it should also withstand 16.8V.
The minimum voltage at which it still remains operational is 8.5 volts, but this is already on the very verge of shutting down; as soon as the voltage drops a little lower, the oscilloscope reboots.
Power consumption is approximately constant - about 36.5 watts with the oscilloscope application running and about 31.2 watts with the application closed. But a force-closed application automatically restarts after a while
This all means that the oscilloscope can be powered from both a 4S battery (12-16.8V) and a 3S battery (9-12.6V).
The voltages shown in the photo on the power supply are inflated to compensate for the voltage drop on the wires. At the same time, the oscilloscope received almost exactly 9V and 16.8V.

[Veteran68]

I think it was clear the scope would at least operate on 12V considering the prototype power supply originally reported was a fixed (not PD) 12V supply. Since 12V is an optional, not mandatory, profile in the PD 3.x spec, while 15V is mandatory, I expect they negotiate 15V for widest PD supply compatibility.

[Demon Xanth]

I mounted mine with an arm and spacers for the plate. The arm I got is setup so a single thumbscrew is all it takes to remove it. I had a spacer made up to mount it below my microscope arm so I only have a single pole taking up space. I also attached a probe holder to the arm to keep them out of the way. Super convenient and no more permanent than it needs to be.

[Randy222]

I experimented with the supply voltage of the oscilloscope by connecting it to a laboratory power supply. The oscillograph works normally at a voltage from 9 to 16.8 volts, I was afraid to give more, not knowing what circuit it has at the power input. But since it is normally powered by 15 volts on its native power supply, it means it should also withstand 16.8V.
The minimum voltage at which it still remains operational is 8.5 volts, but this is already on the very verge of shutting down; as soon as the voltage drops a little lower, the oscilloscope reboots.
Power consumption is approximately constant - about 36.5 watts with the oscilloscope application running and about 31.2 watts with the application closed. But a force-closed application automatically restarts after a while
This all means that the oscilloscope can be powered from both a 4S battery (12-16.8V) and a 3S battery (9-12.6V).
The voltages shown in the photo on the power supply are inflated to compensate for the voltage drop on the wires. At the same time, the oscilloscope received almost exactly 9V and 16.8V.

The DHO800 and perhaps the 900 use about 34w of power.

@12vdc you are max'ing out USB-C connector spec, and have surpassed std cable spec for amps.

It would really be best for equip like this to run on 24vdc to keep supply amps lower, and/or use a better connector, USB-C is not really a good choice, std barrel would have been better. Save USB-C for data.

[Veteran68]

The DHO800 and perhaps the 900 use about 34w of power.

@12vdc you are max'ing out USB-C connector spec, and have surpassed std cable spec for amps.

Huh? USB-C PD is rated up to 5A. Many laptops run at 20V 5A all day long on a USB-C port. USB-C PD 3.1 spec goes up to 48V 5A, so 240W. 12V3A is not even remotely pushing the limits of the USB-C connector. As far as cables go, 3A at 5V is the minimum current that a USB-C cable must support to even legally call itself a USB-C cable.

[AndyBig]

I think it was clear the scope would at least operate on 12V considering the prototype power supply originally reported was a fixed (not PD) 12V supply. Since 12V is an optional, not mandatory, profile in the PD 3.x spec, while 15V is mandatory, I expect they negotiate 15V for widest PD supply compatibility.

I was more interested in whether it would work on 9 volts to power it from 3S batteries

The DHO800 and perhaps the 900 use about 34w of power.

Even more than 36 watts.

It would really be best for equip like this to run on 24vdc to keep supply amps lower, and/or use a better connector, USB-C is not really a good choice, std barrel would have been better. Save USB-C for data.

Well, we have what we have. If desired, you can insert a power connector into the wall of the case.

[AndyBig]

Photos of the disassembled Liteon power supply - https://www.eevblog.com/forum/testgear/rigols-new-dho800-oscilloscope-unbox-teardown/msg5248569/#msg5248569

[AndyBig]

I also attached a probe holder to the arm to keep them out of the way. Super convenient and no more permanent than it needs to be.

Great idea, thanks! It will be necessary to print a similar holder for probes too

[Randy222]

The DHO800 and perhaps the 900 use about 34w of power.

@12vdc you are max'ing out USB-C connector spec, and have surpassed std cable spec for amps.

Huh? USB-C PD is rated up to 5A. Many laptops run at 20V 5A all day long on a USB-C port. USB-C PD 3.1 spec goes up to 48V 5A, so 240W. 12V3A is not even remotely pushing the limits of the USB-C connector. As far as cables go, 3A at 5V is the minimum current that a USB-C cable must support to even legally call itself a USB-C cable.

Amps is the only thing that matters with USB-C. The physical spacing between connector pins both in port and on board, along with the insulation used on wires, can withstand much more than 48vdc. So the "power" rating does not mean too much for USB-C cables and connectors. If PD agrees for 20vdc and the cable is 5A rated, you get good 100w transfer. If PD agrees 48vdc and the cable is 5A rated, you get good 240w transfer.

DHO is about 34w. This maps to about 2.3A@15vdc for the DHO. Going to 12vdc you'll be up'ing the amps by about +0.6 (2.9A), taking it close to std cable max. 5A cable, then all good, but why increase amps, makes no sense to me.

5A on cables that are 5A rated. 5A is the std connector rating.

[AndyBig]

Amps is the only thing that matters with USB-C. The physical spacing between connector pins both in port and on board, along with the insulation used on wires, can withstand much more than 48vdc. So the "power" rating does not mean too much for USB-C cables and connectors.

5A on cables that can handle it. 5A is the connector rating.

Almost any cable will withstand 5A, the only question is how many volts will be lost on it The cable that I used (a cheap, worthless cable) to connect has a resistance of each power core of 70 mOhm, which means that at 5A it will drop 0.07*2*5=0.7V. Unpleasant, but not too critical

[Randy222]

I think it was clear the scope would at least operate on 12V considering the prototype power supply originally reported was a fixed (not PD) 12V supply. Since 12V is an optional, not mandatory, profile in the PD 3.x spec, while 15V is mandatory, I expect they negotiate 15V for widest PD supply compatibility.

I was more interested in whether it would work on 9 volts to power it from 3S batteries

The DHO800 and perhaps the 900 use about 34w of power.

Even more than 36 watts.

It would really be best for equip like this to run on 24vdc to keep supply amps lower, and/or use a better connector, USB-C is not really a good choice, std barrel would have been better. Save USB-C for data.

Well, we have what we have. If desired, you can insert a power connector into the wall of the case.

I rounded off your HY PSU display #'s 17x2, but yep, 37.x watts from your PSU at that higher voltage.

37w @12vdc exceeds std USB-C cable specs. If it's a 5A rated cable, then ok. But why would anyone want to lower voltage for more amps? If anything, I want smaller wire (less used space on my desk, more flexible) with less amps.

[Randy222]

Amps is the only thing that matters with USB-C. The physical spacing between connector pins both in port and on board, along with the insulation used on wires, can withstand much more than 48vdc. So the "power" rating does not mean too much for USB-C cables and connectors.

5A on cables that can handle it. 5A is the connector rating.

Almost any cable will withstand 5A, the only question is how many volts will be lost on it The cable that I used (a cheap, worthless cable) to connect has a resistance of each power core of 70 mOhm, which means that at 5A it will drop 0.07*2*5=0.7V. Unpleasant, but not too critical

Agreed.
I was just noting actual USB-C specs.
But my statement still holds, why up the amps going form 15v to 12v? 

[AndyBig]

But my statement still holds, why up the amps going form 15v to 12v? 

When powering the oscilloscope? This is the property of switching voltage converters - it takes from the source the same power that it supplies to the load (plus its own losses, that is, its efficiency). Therefore, if the source voltage decreases, the current taken from it increases in order to maintain the same power.
And if the question is why make a 9-12 volt 3S battery, then the point is compactness. For example, a 3S2P battery will be light and compact, providing about 2 hours of power to the oscilloscope

[Veteran68]

The specs you posted in that image show minimum required specs of 3A for cables and 5A for connectors, as I stated.

You said:

@12vdc you are max'ing out USB-C connector spec, and have surpassed std cable spec for amps.

which is entirely untrue on both counts.

36W at 12V is 3A. That meets even the minimum specs. It's nowhere near stressing the connector nor any remotely decent cable. I'm not sure why you're so concerned about 2.3A vs 2.9A when either are about half the connector spec and within the minimum cable spec? As you said, almost any cable is going to meet a 3A spec. Sure if you have a 100W+ device you want to be sure to spec a higher quality cable. But at these current levels you're not in any kind of exceptional territory with standard cables and connectors.

[Proxy64]

Mount the DHO to an arm: In fact, this is an extremely convenient option

Any issue with the weight of the oscilloscope ?
His weight is below 2Kg, and all arms I have checked begin at 2Kg and even 3Kg.

[voltsandjolts]

Any issue with the weight of the oscilloscope ?
His weight is below 2Kg, and all arms I have checked begin at 2Kg and even 3Kg.

Add weight to the arm if the scope is too light, like Ian did in his vesa mount video:
https://youtu.be/iB-SsFZvqiE?feature=shared

[Proxy64]

Any issue with the weight of the oscilloscope ?
His weight is below 2Kg, and all arms I have checked begin at 2Kg and even 3Kg.

Add weight to the arm if the scope is too light, like Ian did in his vesa mount video:
https://youtu.be/iB-SsFZvqiE?feature=shared

I saw this, but in fact I would like to avoid this hack, I would prefer to mod the arm if needed or better found one from 1Kg, for now only arms for mic or tablet begin at lower weight, and often need to adapt a vesa head.

[AndyBig]

Any issue with the weight of the oscilloscope ?
His weight is below 2Kg, and all arms I have checked begin at 2Kg and even 3Kg.

I have a bracket with adjustable force of the pneumatic cylinder. At the minimum adjusted force, the oscilloscope is held stably at the set height without trying to rise.

[bikeNomad]

I've attached a version of the rigol unlock tools batch file translated to a .sh file for those of us using Mac computers. It still requires having adb and the Go language installed.

However, my DHO914 is not accepting the generated BW15T25 option SCPI command (no generated .lic file), either with the original 00.01.00 or now the 00.01.01 firmware downloaded from the rigolna site.

EDIT: and also not accepting the option with the 00.01.02 firmware posted here.

Has anyone succeeded in increasing the bandwidth of a real DHO914 this way on either of those firmwares?