a modular irrigation controller includes a processor capable of executing a stored watering program and controlling a plurality of removable station modules in accordance with the watering program . each station module includes a station module circuit for opening and closing a plurality of valves . a plurality of connectors can mate each mate to establish a communications link between the station modules and the processor . a plurality of terminals are each connectable with a corresponding one of a plurality of field valve lines from the valves . the terminals are mounted separate from the station modules and are connected to the connectors . this allows the irrigation controller to have a more compact design , provides connection terminals for spare field valve lines , and eliminates malfunctions due to erroneous re - connection of field valve lines during station module replacement .