Rigol DHO800/900 Oscilloscope Bug Reports + Firmware

[dzungpham0703]

I have problem with decode function for LIN signal. I try RS232 it fine, but with LIN data, it could not detect the data, only show wake-up signal.
Also it very hard to detect the signal because my data only send each 2 seconds, all parameter must do manual until see the data signal.
I do it wrong or this is a bug of this scope?
My signal is 2400 baud, probe 1X, the lowest speed support by DHO900 series.

[Howardlong]

SPI decode still doesn't work on the digital channels under 1.02 firmware, so back in the drawer it goes.

[voltsandjolts]

SPI decode worked for Martin on the DHO804, maybe a setup or SPI freq issue?
https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5177292/#msg5177292

[Fungus]

SPI decode worked for Martin on the DHO804

It works on the analog channels but not the digital (apparently).

[Howardlong]

SPI decode worked for Martin on the DHO804, maybe a setup or SPI freq issue?
https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5177292/#msg5177292

"SPI decode still doesn't work on the digital channels under 1.02 firmware, so back in the drawer it goes."

[LarsRo]

There are some bugs related to LAN, LXI, mDNS/Bonjour:

• mDNS is disabled after reboot.
  According to https://www.lxistandard.org/Documents/about/LXI%201_3%202008-10-30.pdf, Rule 10.5, "Both mDNS and DNS-SD shall be enabled by default on LXI Devices."
  It is rather inconvenient to have to activate mDNS manually every time you start the scope.
• The port number for the connection to the oscilloscope for control with SCPI commands is 5555.
  This should be 5025 (Scpi-raw) or 5024 (Scpi-telnet), according to https://www.lxistandard.org/About/LXI-Protocols.aspx
  
• mDNS is incorrectly giving port 80 as the port for the services _scpi-raw and _lxi.
  For _scpi-raw it should be 5555 (unless changed to 5025, of course).
  Under port 80 you find the web interface of the scope.

[csuhi17]

DHO924S
hardware: 8
and firmware 00:01:00
I haven't had time to properly test it yet, but I found two bugs that were solved by the 00:01:01 update.
First, if I changed the frequency of the AWG with the knob, my program kept crashing above 10kHz.
Second, the UltraAquire function did not work.
luckily the update fixed it.

[akkk44]

Here I got something:
Feeding in 1Vpp 120Mhz sine wave singnal.
Trigger at below -340mV
A strange second waveform will start to appear and flicker. (Won't happen above this triggering level)


Edit: The sine wave signal was generated by a siglent SDG2122X(converted from SDG2042X). The oscilloscope was 50ohm terminated with the terminator from rigol and the BNC cable was from the siglent SDG. The oscilloscope was DHO804 on F/W 01.02 and was hacked to DHO924.
I have also tried lowering the frequency and it did improve as the frequency gets lower. However, it can still occasionally happen at 70MHz.

Edit 2: One more thing I want to mention is that the displayed Vpp on F/W 01.02 was noticeably higher than F/W 01.14, both hacked to 250M.

Edit 3: A source said that reloading the version-related FPGA bit inside the F/W package can ease this issue. I have tested this by reloading the BOOT.bin provided in the F/W upgrade package and it did help, but did not eliminate the problem.

[csuhi17]

Here I got something:

it's the same for me. 924S
try setting the trigger to the falling edge if you trigger the bottom of the wave.
For the top, use the rising edge trigger.
and look at "Either" as well.

[Fungus]

Here I got something:
Feeding in 1Vpp 120Mhz sine wave singnal.
Trigger at below -340mV
A strange second waveform will start to appear and fliker.

This is NOT a bug, you have something in your signal that's causing false triggers.

Adjust trigger settings until it goes away.

it's the same for me. 924S
try setting the trigger to the falling edge if you trigger the bottom of the wave.
For the top, use the rising edge trigger.
and look at "Either" as well.

It's the same for everybody on every oscilloscope ever made.

The solution is to adjust the trigger, as you noticed.

[csuhi17]

Yes, it needs to be set up well.
My other scopes do not produce this.
maybe the Micsig TO2202C, but it's already at the bottom of the signal, it can't trigger well.
I think this event is more noticeable with this scope.

[Fungus]

I think this event is more noticeable with this scope.

12-bit resolution is more sensitive to noisy signals.

[ebastler]

I think this event is more noticeable with this scope.

12-bit resolution is more sensitive to noisy signals.

There is a "Noise Rejection" switch in the trigger dialog which might help. It is not explained well in the user manual, but I assume it sets some hysteresis for the trigger threshold. (It does not enable a low-pass filter, presumably, since there is a separate "high frequency rejection" option for trigger coupling.)

[2N3055]

I think this event is more noticeable with this scope.

12-bit resolution is more sensitive to noisy signals.

NOOOOOOO it is not....
12 bit actually allows for more accurate trigger point interpolation, and less trigger jitter....

It might be that signal has some very fast spikes not visible at this magnification. Trying noise rejection like Ebastler suggested would be good idea to try. Also LF/HF trigger filter...

[Fungus]

NOOOOOOO it is not....
12 bit actually allows for more accurate trigger point interpolation, and less trigger jitter....

Well, that's the "Let's keep this thread clean and noise free" edict down the toilet...

It is NOT a bug. That's all that needs to be said here.

Any other discussion? How about in the other thread where OP also posted it?

[akkk44]

Here I got something:
Feeding in 1Vpp 120Mhz sine wave singnal.
Trigger at below -340mV
A strange second waveform will start to appear and fliker.

This is NOT a bug, you have something in your signal that's causing false triggers.

Adjust trigger settings until it goes away.

it's the same for me. 924S
try setting the trigger to the falling edge if you trigger the bottom of the wave.
For the top, use the rising edge trigger.
and look at "Either" as well.

It's the same for everybody on every oscilloscope ever made.

The solution is to adjust the trigger, as you noticed.

Thank you, I got confused there as I am expecting to find some abnormally on F/W 01.02 and I just think this is one of them. I later realized this happens all the time but can't quite figure out why as this won't happen on my Siglent 1102x-c or Agilent 3032A. I will try tomorrow, thanks again.

Edit: After enabling the "Noise Rejection" function, the oscilloscope stops triggering at the low voltage level on the "rising edge" trigger type.

Edit2: To clarify: The "Noise Rejection" function did prevent the "ghost waveform" from appearing as it won't trigger below -340mV anymore with the "rising edge" trigger type. I will need to switch to the "falling edge" trigger type  for a stable trigger.

Edit3: I have added more information at #133.

[JDW]

SPI decode worked for Martin on the DHO804, maybe a setup or SPI freq issue?
https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5177292/#msg5177292

"SPI decode still doesn't work on the digital channels under 1.02 firmware, so back in the drawer it goes."

I have checked most of the Rigol sites worldwide, including their Chinese site here (click the 4th tab from the right to see firmware), and only Firmware version 1.01 is currently available as of Nov. 28, 2023.  So if you are not mistaken about there being a version 1.02, please provide the source and a link to it.  Thanks.

[rf-loop]

I think this event is more noticeable with this scope.

12-bit resolution is more sensitive to noisy signals.

In this context..   

If I need good noise (aka bullshit) generator...  I will buy you for this work... how much you want salary. 

[Fungus]

12-bit resolution is more sensitive to noisy signals.

In this context..   

 

Sorry, should I have said "less-than-perfect" signals?

Edit: After enabling the "Noise Rejection" function, the oscilloscope stops triggering at the low voltage level on the "rising edge" trigger type.

Oh, look, the "noise" rejection function fixed it! How is that possible? 

[2N3055]

12-bit resolution is more sensitive to noisy signals.

In this context..   

 

Sorry, should I have said "less-than-perfect" signals?

Edit: After enabling the "Noise Rejection" function, the oscilloscope stops triggering at the low voltage level on the "rising edge" trigger type.

Oh, look, the "noise" rejection function fixed it! How is that possible? 

You misunderstood. He said that if he enables "Noise Rejection" function it stop triggering completely on rising edge type when trigger level is low...

So something is wrong. Either some user error or problem with trigger.

[Fungus]

So something is wrong. Either some user error or problem with trigger.

Definitely not the signal combined with 12-bit resolution?

PS: It cured his false triggers... leading him to the correct solution of adjusting the trigger level.

[2N3055]

So something is wrong. Either some user error or problem with trigger.

Definitely not the signal combined with 12-bit resolution?

PS: It cured his false triggers... leading him to the correct solution of adjusting the trigger level.

12 bit resolution should make triggering more stable... Like I said...

Quote:

Edit: After enabling the "Noise Rejection" function, the oscilloscope stops triggering at the low voltage level on the "rising edge" trigger type.

Where do you see word fixed?

[csuhi17]

The test signal was provided by a TinySA Ultra.
In the video, I set the simple edge trigger.
The frequency can be seen on the side, as well as the value of Vpp.
and in the pictures you can see it at 4 frequencies.
At 125Mhz and 250Mhz, you can see that the bad triggering zone is larger, that is, the value of deltaY compared to the total Vpp.
I can't reproduce this phenomenon as strongly on another scope.

[ebastler]

Thanks for sharing the video. And ouch, that looks wrong indeed...

In the experiments with the bi-directional edge trigger setting, the effect might be due to the phase of the sine wave where the trigger gets activated. At certain trigger levels you might always "catch" the sine wave at such a time that the next re-trigger again sees the same edge direction, while at other levels, the active edges alternate? So that would not be a bug.

But I don't have an explanation for the unexpected trigger points in the positive or negative edge setting. The trigger often "strikes" when the signal level is far away from the set trigger threshold. Clearly a bug, I'd say.

[2N3055]

The test signal was provided by a TinySA Ultra.
In the video, I set the simple edge trigger.
The frequency can be seen on the side, as well as the value of Vpp.
and in the pictures you can see it at 4 frequencies.
At 125Mhz and 250Mhz, you can see that the bad triggering zone is larger, that is, the value of deltaY compared to the total Vpp.
I can't reproduce this phenomenon as strongly on another scope.

Are you using Auto trigger mode? Try using normal trigger mode..