Lua controllers that use interrupts will continue running after the player leaves the area or logs off. Each time the interrupt fires, it force loads the mapblock and runs the lua code which probably sets up another interrupt. The mapblock is loaded as inactive so most stuff won’t work, but the lua controller can output signals which conduct through mesecon wires and can trigger events in other lua controllers. And these mapblocks keep reloading until the server restarts.
I wrote a script that can detect a loaded mapblock, and can be used to turn off “machines” when an area is unloaded. A node detetector is pointed at an adjacent mapblock that must not have lua controllers using interrupts in it or wires coming from luacontrollers outside the mapblock (otherwise it won’t unload and the script won’t work). When the mapblock unloads, the lua controller turns off its output and stops scheduling interrupts. The output signal can be used to turn on/off a larger “machine”. A blinking plant next to the lua controller will turn it back on when the area is loaded again.
There is an example on the back wall in the basement of my gold farm, for anyone who wants to use this.