Solution
To prevent a user from stopping a DIAdem DAC execution, you can disallow the manual abortion.
To do that, you change to the DIAdem DAC workspace and click on
Settings >> Single Point Processing >> Measurement Parameters... .
In the popup window, you uncheck the box
Allow manual aborting.
After you saved the settings and start the DAC diagram, the Stop Measurement button is grayed out, and pressing ESC does not have an effect.