How to only log data on a certain event?

Question

I am working on a TwinCAT 3 system where a stepper motor moves a linear axis at 40 mm/s, and I need to record sensor values (analog 0–10V) only when the position changes by 0.1 mm. This means I need a sampling rate of 400 Hz (every 2.5 ms), but instead of logging at a fixed time interval, I want to log only when new position data is available.

What I’ve tried:

• Trigger-Based Approach in Scope View:
  I tried using a trigger variable (bTrigger := TRUE when position changes by 0.1 mm), but Scope View does not seem to support event-based logging.
• Filtering Data in PLC Code:
  I modified my PLC program so that sensor values update only when the position changes, but Scope View still records at a fixed time interval, logging redundant data.
• Using TwinCAT TF6420 Scope Server:
  I read that TF6420 Scope Server might allow event-based logging, but I am not sure how to configure it correctly (or if it's necessary).

My questions:

• Is there a way to configure TwinCAT Scope View to log only when position changes by 0.1 mm instead of a fixed time interval?
• If direct event-based logging is not possible, what is the best workaround to achieve a similar result?
• Would TF6420 Scope Server be required for this, or is there a solution using standard TwinCAT 3 Scope View?

I am new to Beckhoff (coming from Siemens PLCs), so any guidance or example configurations would be very helpful!