Can the loading of the application onto the PLC be time-limited?

Yes.
If the loading of the application onto the PLC has not been finished within of 20 seconds, Neuron Power Engineer reports a timeout. If you want to define a smaller or larger time period, define a different timeout:

  1. Go to the folder where you installed Neuron Power Engineer.

  2. Locate the file NeuronPowerEngineer.ini and open it in a text editor.

  3. Enter -DUploadTimeout with a value in milliseconds after the option -vmargs.

    Example 
    ...
    -vmargs
    -Dosgi.requiredJavaVersion=1.8
    -Xms256m
    -Xmx6144m
    -DUploadTimeout=30000

  4. The value 30000 corresponds to 30 seconds.

  5. Save the file.

  6. Start Neuron Power Engineer and load the application onto the PLC.
    If it is not possible to load the application within the defined time period (hence within the defined 10 seconds), this message is displayed: Timeout while executing target command "ACTIVATE" (IP address of target is IP address)