i really need your help urgently :
i have an assignment for controlling set of pumps ofr water treatment plants depending on a level of water there three functions in the program:
1-to work one pump depending on msgs from the level switcheseither Auto or Manu (one pump is running the other is Standby.
2- the two pumps should work if the high switch operated give its signal .
the third thing that the system now is owrking on alternator to switch in between the pumps the working one to stop and the standby to work when this Alternator is activated and it activated using a low low level switch .
i know its not that clear i just need the Idea of the LAternator .