the entire disclosures of the following patents and applications are hereby incorporated by reference : u . s . pat . no . 5 , 097 , 861 granted mar . 24 , 1992 of hopkins et al . entitled irrigation method and control system ; u . s . pat . no . 5 , 444 , 611 granted aug . 22 , 1995 of peter j . woytowitz , et al . entitled lawn and garden irrigation controller ; u . s . pat . no . 5 , 829 , 678 granted nov . 3 , 1998 of richard e . hunter et al . entitled self - cleaning irrigation regulator valve apparatus ; u . s . pat . no . 6 , 088 , 621 granted jul . 11 , 2000 also of peter j . woytowitz et al . entitled portable apparatus for rapid reprogramming of irrigation controllers ; u . s . pat . no . 6 , 721 , 630 granted apr . 13 , 2004 also of peter j . woytowitz entitled expandable irrigation controller with optional high - density station module ; u . s . pat . no . 6 , 842 , 667 granted jan . 11 , 2005 of beutler et al . entitled positive station module locking mechanism for expandable irrigation controller ; pending u . s . patent application ser . no . 10 / 848 , 394 filed may 17 , 2004 also of peter j . woytowitz entitled isolated modular expandable irrigation controller ; pending u . s . patent application ser . no . 10 / 883 , 283 filed jun . 30 , 2004 also of peter j . woytowiz entitled hybrid modular / decoder irrigation controller ; pending u . s . patent application ser . no . 10 / 985 , 425 filed nov . 9 , 2004 also of peter j . woytowitz et al . and entitled evapotranspiration unit connectable to irrigation controller ; and pending u . s . patent application ser . no . 11 / 045 , 527 filed jan . 28 , 2005 also of peter j . woytowitz entitled distributed architecture irrigation controller . the aforementioned patents and applications are all assigned to hunter industries , inc ., the assignee of the subject application . referring to fig1 and 2 , an irrigation controller 10 in accordance with an embodiment of the present invention includes a wall - mountable plastic structure including a generally box - shaped front door 12 hinged along one vertical edge to a generally box - shaped back panel 14 ( fig3 ). a generally rectangular face pack 16 ( fig2 ) is removably mounted over the back panel 14 and is normally concealed by the front door 12 when not being accessed for programming . the face pack 16 has a plurality of manually actuable controls including a rotary dial switch 18 and push button switches 19 , 20 , 21 22 , 23 , 24 and 25 as well as slide switch 26 , which can be manipulated in conjunction with numbers , words or graphic symbols indicated on a liquid crystal display 28 for entering or selecting a watering program as is well known in the art of electronic irrigation controllers . custom watering programs can be created by the user by manipulating the rotary dial switch 18 and selected ones of the push button switches 19 , 20 , 21 22 , 23 , 24 and 25 . alternatively , existing pre - programmed watering programs can be selected , such as watering all zones every other day for five minutes per zone . the face pack 16 ( fig1 and 2 ) supports a main circuit board assembly ( not illustrated ) with a processor , hereafter described , for executing and implementing a stored watering program . an electrical connection is made between the face pack 16 and the components in the back panel 14 through a ribbon cable 29 ( fig4 ). the circuitry inside the face pack 16 can be powered by a battery to allow a person to remove the face pack 16 , un - plug the ribbon cable 29 , and walk around the lawn , garden area or golf course while entering a watering program or altering a pre - existing watering program . the stored watering program can be a complex set of run time and cycle programs , or a portion thereof , such as a simple five minute cycle for a single station . female multi - pin electrical connectors 30 ( fig4 ) mounted in the underside walls of six removable rectangular station modules 31 - 36 ( fig3 ) receive corresponding male multi - pin electrical connectors 38 ( fig4 ). the modules 31 - 36 are received in side - by - side fashion in outwardly opening rectangular receptacles formed in a plastic support structure 40 mounted within the back panel 14 ( fig3 ). the male multi - pin connectors 38 are mounted in the receptacles . the back panel 14 is a separate housing from the face pack 16 that encloses the processor , the functions of which are hereafter described in greater detail . the module 31 may be a master module that interfaces with a pump and sensor ( not illustrated ). a locking bar 42 can be manually slid left and right in fig3 between locked and unlocked positions to secure and un - secure the station modules 31 - 36 in their receptacles as disclosed in the aforementioned u . s . pat . no . 6 , 842 , 667 . a raised projection 44 on the locking bar 42 is grasped between the thumb and index finger to slide the locking bar 42 . the raised projection 44 also serves as a position indicator that aligns with modules locked indicia and unlocked indica formed on the upper surface of another plastic support structure 46 mounted inside back panel 14 . fig4 is a block diagram of an irrigation system that includes the controller 10 . a processor 50 mounted in the face pack 16 executes a selected watering program stored in a program memory ( pm ) 52 using a data memory ( dm ) 54 . the pm 52 may be provided as a read only memory ( rom ), a flash memory , or other suitable permanent or semi - permanent micro - electronic memory . the dm 54 is preferably a random access memory ( ram ). the processor 50 may comprise a microprocessor that uses separate memory , or a micro - computer with on - chip memory that serves the same functions as the pm 52 and dm 54 . the manually actuable controls and the display of the controller 10 are not illustrated in fig4 for the sake of simplicity . they are interfaced with the processor 50 in the usual fashion . the processor 50 is connected through suitable input / output ( i / o ) devices ( not illustrated ), an electro - optic isolator ( not illustrated ) and a bus 56 that is routed through the ribbon cable 29 to the station modules 31 - 36 in the back panel 14 . the processor 50 ( fig4 ) controls the station modules 31 - 36 . serial or multiplexed communication is enabled over the bus 56 so that all of the information as to which stations or zones should be turned on and off at any given time is present at each receptacle . a twenty - four volt ac power signal from a transformer 58 plugged into a wall outlet is supplied to each of the station modules 31 - 36 over a pair of lines 60 . the twenty - four volt ac power is used by the modules 31 - 36 for switching a plurality of solenoid actuated valves 62 between on and off states . the twenty - four volt ac power signal from the transformer 58 can also be used by a master module in order to control a pump or master valve ( not illustrated ). dc power is supplied by the power supply ( ps ) 64 to the face pack 16 via line 68 that extends within the ribbon cable 29 . typically the solenoid actuated valves 62 are mounted in subterranean plastic boxes ( not illustrated ) relatively close to the controller 10 , i . e . within one hundred feet of the controller 10 . the valves 62 control the supply of pressurized water through subterranean pvc pipes ( not illustrated ) equipped with risers and sprinklers ( not illustrated ). as used herein , the term “ valve ” includes any type of remotely controlled valve useable in an irrigation system . the term “ valve ” includes valves of the general type in which a solenoid controls a diaphragm type valve . see for example , the valve disclosed in u . s . pat . no . 6 , 079 , 437 granted jun . 27 , 2000 of beutler et al ., assigned to hunter industries , inc . the term “ valve ” also includes valves in which a pilot valve is not directly opened and closed by a solenoid , e . g hydraulically or pneumatically actuated valves that have a solenoid or its electrical equivalent somewhere in the fluid system , and not necessarily next to the gating valve , for controlling the fluid pressure to open and close the valve . a suitable electrical port ( not illustrated ) may be connected to the processor 50 for downloading a watering program that has been created on a personal computer and downloaded into a smart card , portable data shuttle or other removable media ( not illustrated ). alternatively , the processor 50 may receive programming and / or commands from a master computer and / or the internet via hard - wired or wireless connection . the processor 50 could also receive data and commands through a satellite receiver ( not illustrated ). the programming executed by the processor processor 50 can include a cleaning cycle which momentarily turns on each valve 62 after completion of a run cycle to flush debris away from the valve seat . see the aforementioned u . s . pat . no . 5 , 829 , 678 . the station modules 31 - 36 ( fig4 ) are configured for insertion into corresponding receptacles in the back panel 14 . the station modules 31 - 36 are connectable to corresponding solenoid actuated valves 62 through dedicated field valve lines 70 . the valves 62 are all connected to a common return line 72 . the lines 70 and 72 may comprise insulated twelve gauge wires whose stripped ends are secured to the screw terminals of a pair of terminal strips 74 and 76 ( fig3 ) mounted on support structure 46 physically separate and remote from the station modules 31 - 36 . the station modules 31 - 36 each include a micro - controller ( not illustrated ) and at least one switching device , such as a triac ( not illustrated ) for selectively supplying the twenty four volt ac power signal from the transformer 58 that energizes the corresponding solenoid actuated valve 62 . in the example shown , the station modules 31 - 36 each include four switching devices and can independently control four separate valves 62 . suitable synchronous serial data and asynchronous serial data station module circuits are disclosed in the aforementioned u . s . pat . no . 6 , 721 , 630 . the individual screw terminals of the terminal strips 74 and 76 are connected to individual pins of the male multi - pin electrical connectors 38 so that the triacs of the station modules 62 can selectively apply the twenty - four volt ac signal to the field valve lines 70 . in other words , one of the pins in each of the male multi - pin electrical connectors 38 is hard - wired to a corresponding screw terminal of one of the terminal strips 74 and 76 . one of the remaining pins of each male multi - pin connector 38 is used to carry power to the corresponding station module circuit from the transformer 58 . the remaining pins of each male multi - pin connector 38 are used to establish a communications link between the processor 50 and each of the station modules 31 - 36 . the terminal strips 74 and 76 could be replaced with a wide variety of terminals . as hereafter used in the claims the term “ terminals ” encompasses any type of electro - mechanical device suitable for easy and reliable connection and disconnection of the field valve lines 70 . where the field valve lines 70 are wire , such terminals include not only screw and lever type terminals , but many others such as those used on the rear of audio amplifiers , speakers , ac wiring , auto electric systems and so forth . similarly , the mating multi - pin electrical connectors 30 and 38 could be replaced with a wide variety of other types of mating electrical connectors . as used in the claims the term “ connectors ” encompasses any type of electro - mechanical devices suitable for rapid connection and disconnection of the station modules , including , but not limited to , multi - pin electrical connectors , card edge connectors and various multiple conductive path male / female plug configurations . another terminal strip 78 ( fig3 ) is mounted on support structure 46 . the terminal strip 78 provides screw terminals 80 and 82 that allow auxiliary devices to be connected to ac power and a screw terminal 84 for connecting a ground wire . another terminal strip 86 is mounted on support structure 46 and provides screw terminals 88 , 90 and 92 for connecting remote sensor inputs , such as a rain interrupt sensor or an evapotranspiration module , and / or other auxiliary devices ( not illustrated ). the common return line 72 is connected to one of the screw terminals of either terminal strip 78 or terminal strip 86 . the use of terminals separate from the station modules allows the controller 10 to be re - configured so that the station modules 31 - 36 can be stacked , i . e . inserted one on top of the other . this allows for a reduction in the overall size of the controller 10 . installation is also simplified since extra field valve lines 70 ′ ( fig4 ) can be connected to terminals , even before the extra station modules , 32 - 36 for example , are purchased and installed . service is also simplified since a defective station module can be quickly unplugged and replaced without disturbing or disconnecting any of the wiring to the valves 62 . the system of fig4 can be modified to function as a hybrid modular / decoder controller as disclosed in the aforementioned u . s . patent application ser . no . 10 / 883 , 283 . fig5 is a block diagram of an irrigation system including a hybrid modular / decoder irrigation controller 100 . the station module 31 is replaced with an encoder module 102 and some of the valves 104 have decoder circuits 106 so that they can be controlled by the processor 50 over the same pair of field valve lines 108 that together form a common multi - wire path . just as in the system of fig4 , to the field valve lines 108 to the valves 104 are attached to one of the terminal strips 74 and 76 separate from the encoder module 102 . the field valve lines 108 could be optical fibers since the valves 104 may have local power sources . in such a case the connectors could include fiber optic connectors and opto - electronic couplers to provide communications through the terminal strips 74 and 76 to the processor 50 . while i have described exemplary embodiments of a modular irrigation controllers with separate filed valve line wiring terminals , it will be apparent to those skilled in the art that the invention can be modified in both arrangement and detail . as an example , the controller 10 could be designed to control a predetermined number of valves , e . g . four , without requiring the insertion of any station modules . as another example , the system of fig5 could be modified to eliminate the station modules 32 - 35 and replace them with encoder modules . therefore , the protection afforded the invention should only be limited in accordance with the following claims .
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 .