Rigol DS4024 Vertical Position Erratic Behavior

[pizzyflavin]

Hey everyone, I recently bought a DS4024 directly from Rigol with the serial decode option and the 350 MHz bandwidth upgrade. Everything seems to work fine except for an issue with adjusting the vertical position of a trace. When trying to move a trace up or down on the screen of the scope, often times the trace will just jump several divisions, or off the screen entirely. For instance, say I'm trying to look at some SPI signals, and I want to adjust the traces so I can see the SCLK, MISO, and CS all at the same time. I'll move the traces up or down to try to get them in position, but as I'm moving a trace it just keeps jumping, even when adjusting very (VERY) slowly. This is extremely frustrating, and it makes an otherwise great scope difficult to use.

I know I've seen people talk about slow vertical position, and other issues having to do with the trace moving up or down while adjusting V/div, but this is a separate issue. Has anyone else seen this behavior?

[IDEngineer]

My DS4024 is a couple of years old now, also straight from Rigol with the serial decode package. I haven't seen this behavior on the vertical position controls, but I do see "jumpiness" in the V/Div controls. It's even more pronounced on the horizontal position control, which often misses many steps during large adjustments - sometimes I'll rotate it a full spin or more and nothing changes. I've learned to stop for a moment and then restart the adjustment.

It "feels" like the interface to some of the front panel controls has something like a race condition. From all the comments, it appears to affect many front panel controls and not just one in particular, which is what makes me think it's an architecture problem. Hopefully in firmware (which could be fixed and reflashed) and not hardware.

Separately: I almost always get a "Parameters overrange!" warning when I adjust any V/Div vertical control. It self-clears after a second or two, and I've learned to ignore it. Only the vertical sensitivity knobs seem to suffer from this, and again - the fact that it affects all four knobs suggests its an architecture thing and not a bad rotary encoder.

[jjoonathan]

It changed from the old, slow-ish-but-not-bad behavior to jumps-at-the-slightest-provocation in the latest firmware "update" (from 2.3.0.3 to whatever the new jumpy one is called). If you can go back to 2.3.0.3, it'll probably fix the issue.

[pizzyflavin]

Thanks for the responses.

IDEngineer, I don't seem to have issues with any controls except for the vertical position on each channel. I just tested my vertical sensitivity knobs, and they don't give me a "parameter overrange" warning unless the adjustment is indeed overrange.

jjoonathan, I do have the latest firmware, I'll try the previous version and let you all know how it goes. I wonder if I'll see the "parameter overrange" warnings on the vertical sensitivity knobs.

[IDEngineer]

IDEngineer, I don't seem to have issues with any controls except for the vertical position on each channel. I just tested my vertical sensitivity knobs, and they don't give me a "parameter overrange" warning unless the adjustment is indeed overrange.

I'd take that as further proof that the front panel control behavior is almost entirely firmware. It might get down to choosing your firmware revision based on the user interface behavior you prefer! 

[bigeblis]

Sounds like anti-shake is not done

[pizzyflavin]

Ok, so while I was looking for older firmware versions, I actually found this article: https://rigol.desk.com/customer/en/portal/articles/2930024-4000-series-vertical-offset-adjustment-speed

Basically, it says that there is some new firmware from October 2017 that shows up as 00.02.03.SP1. In this version, the vertical position knobs have behavior that is tied to the coarse/fine setting of the vertical scale knobs. In other words, if the V/div knob is in "coarse" mode, then the vertical position knob is also "coarse". If it is in "fine" mode, then vertical position is also "fine".

I tested this claim, and it is accurate. Putting the vertical scale into "fine" mode by pushing the knob also puts the vertical position knob in "fine" mode. Regarding the vertical position, I have found "fine" to be acceptable, and "coarse" to be unusable. I guess this kind of solves the problem, so I didn't bother downgrading the firmware. Is there anyone else with a 4000 series willing to test this?