For newbies to Bode plot the simplest mistake is not placing a Tee into the DUT stimulus path to provide a reference signal into the scope.
FG Out should be tee'ed into ch 1 and then to the DUT and the through path into the selected channel provides the info for the scope to plot the result as it sweeps through the set frequency range.
Simply, without providing a reference signal you won't get a result.
Initially I would leave vertical scaling to Auto to be sure to get a result on the display.
This app note for X-E Bode plot might provide some further guidance.
https://siglentna.com/application-note/bode-plot-filter-oscilloscope-generator/
However, do note they are using a standalone AWG and have synced outputs which negates the need to tee the stimulus.
Thanks tautech... At this stage, I'll try anything. Trust me on this, I've tried multiple circuits and literally dozens (if not a hundred) different config settings. They all just hang the scope. Once it's locked-up, it could sit there for an hour and not recover. All the buttons are frozen and it needs a hard power reset to recover. Is that consistent with not using a Tee? I would think that an improper wiring setup would lead to a weird/inaccurate plot result.
It can't make any sensible plot without a reference waveform, period !
We can work also without reference when we know what we are doing and if we think this kind of FRA result meet our need.
Here is scalar plot (no Phase) without any kind of reference.
In this setup DUT out come to CH1. CH4 is set for reference DUT In but there is nothong connected to CH4.
Generator OUT is connected to DUT input.
Naturally in this case we can not get Phase (it generate Phase data but it is bullshit and Phase trace is better to shut off.
Also we loose measured information about DUT input level.
For this kind of application we need select display amplitude mode for
Vout instead of Vout/Vin (because now Vin is unknown!)
In this case I have also turned off Automatic Gain Control (= Hold). (reduced dynamic range but faster sweep.)
Because AGC is off user need set oscilloscope input V/div carefully beforehand when BodePlot is turned off because when BodePlot is on, user can not adjust these (Why channel adjustments are not enabled - perhaps because <censored>). Channels V/div need adjust beforehand so that highest point do not clip but enough close to full scale for get best possible dynamic range over noise level. For this adjustment, make all connection ready and use then SDG manually for find DUT out top level and set V/div so that it can not clip. (keep it so that p-p do not go out of display even if there is some room before ADC really clip. (In some models just before clip it may have also reduced linearity)
I have used maximum points (501) (because span is narrow I use linear freq axis).
One sweep in this case 1min 35sec. (it may also be different with different SDG and connection. I have used here LAN between Scope and SDG1000X)
For this plot there is no reference. CH4 is in this case DUT In and there is nothing connected. I have set BodePlot channels just only for color because here I want yellow plot. (setup can see in other image). Note this noise. Channel Gain mode is Hold! (AGC Off) Turning it to Auto give more dynamic range.