FAQ.How to make my Mac not sleeping?
Feedback.

Answer: Just inform the Mac OS about some system activity with code like this:
Example:

Sub UpdateSystemActivity()
  #if TargetWin32
    'nothing on Windows
  #else
    #if TargetCarbon
      declare function myUpdateSystemActivity lib "CarbonLib" alias "UpdateSystemActivity" (activity as integer) as short
    #else
      declare function myUpdateSystemActivity lib "PowerMgrLib" alias "UpdateSystemActivity" (activity as integer) as short
    #endif
    
    const OverallAct                    = 0 // Delays idle sleep by small amount                 */
    const UsrActivity                   = 1 // Delays idle sleep and dimming by timeout time          */
    const NetActivity                   = 2 // Delays idle sleep and power cycling by small amount         */
    const HDActivity                    = 3 // Delays hard drive spindown and idle sleep by small amount  */
    const IdleActivity                  = 4 // Delays idle sleep by timeout time                 */
    
    dim e as integer
    
    e=myUpdateSystemActivity(UsrActivity)
    
    // you may react on an error if e is not 0 after the call.
    
  #endif
End Sub

Notes:
You may use another constant if you prefer some different behavior.
Call it maybe every second.