Abstract: An apparatus and method that provides an auxiliary timing source for electronic clocks, normally powered by alternating current (ac). The apparatus and method includes calibrating an inexpensive resistor-capacitor oscillator, powered by a battery. The oscillator is calibrated during normal ac operation by comparing a digital timing pulse derived from the oscillator and a digital timing pulse derived from the alternating current. When a power failure occurs, the calibrated oscillator provides an inexpensive and accurate auxiliary timing source. The apparatus and method may also include a non-volatile solid-state storage medium for storing the time of day and a set of timing instructions in the event that the battery becomes drained.

Abstract: An irrigation control system and a related method for controlling a large number of valves in accordance with a plurality of schedules of instructions provided by the user of the system. Schedules of instructions may be created or modified during normal operation of the system by utilizing a variety of command sequences on a keyboard and display device, and schedules may also be reviewed or monitored during operation. The control system includes apparatus for processing a plurality of digital inputs by means of which the conditions of sensing devices located in the field are monitored and can be used to condition execution of the schedules of instructions. The control system is disclosed for use with a two-wire irrigation system in which on/off control signals are encoded into a power signal for transmission along a pair of wires to which decoding units are connected.

Abstract: A method and apparatus for the control of a number of valves in an irrigation system utilizing only two lines between a central encoder and a number of remotely located decoders. An alternating-current signal on the lines is used both to transmit power to the decoders and valves, and to convey control information in the form of decoder addresses and on/off signals represented in binary form by selectively clipping the alternating-current signal. The encoder includes timing and switching circuitry to effect temporary interruptions of the alternating-current signal, and to detect feedback signals transmitted from the decoders during the interruptions. At each decoder, the received control signals are recovered from the power lines, and each received decoder address is compared with one which identifies the decoder. When a match is found, the received on/off signal is employed to switch a valve and to initiate transmission of a confirmatory feedback signal.

Abstract: An improved irrigation control system of the type having a number of irrigation stations to be actuated sequentially, in which selected stations can be actuated for a relatively long time and the others for a relatively short time. In one embodiment, an additional capacitor is automatically connected in parallel with an existing timing capacitor at a time when shrub-watering stations requiring long-term irrigation have been scheduled for operation, when the system is positioned at a shrub-watering station, and when a switch is positioned to select long-term irrigation. In another embodiment, an additional capacitor is automatically connected in parallel with the existing timing capacitor when any one of a selected group of stations is actuated.

Abstract: Apparatus, and a related method, for proportionately varying from a master unit the durations of irrigation at a plurality of valve stations controlled by a number of satellite units, and for transmitting over a single pair of wires control signals for starting a programmed sequence of valve operations at all of the satellites in a selected one of two groups of satellites, or for resetting all of the satellites to a "home" position. One disclosed embodiment includes adjustable timing circuitry in the master unit to generate a timing signal which is transmitted to the satellite units over a separate wire, and is utilized to vary the duty cycle of a station timing motor which measures the durations of irrigation. In an alternate embodiment, station timing at each satellite is measured by means of a digital pulse counter, and the irrigation times at all of the stations can be varied to the same degree by adjustment of a variable-frequency pulse generator at the master unit.

Abstract: A self-cleaning filter assembly for use in a solenoid-actuated valve of the type having fluid pressure-operated diaphragm to control opening and closing of the valve, the diaphragm operating in response to fluid pressure admitted from the inlet chamber of the valve into a control chamber to maintain the valve in a closed position, and when the fluid pressure in the control chamber is relieved by actuation of the solenoid, to open the valve. The self-cleaning filter assembly filters control fluid admitted to the control chamber, and comprises a filter element cleaned by a brush each time the valve is opened or closed, thereby to prevent clogging of the filter during use.

Abstract: Apparatus for the control of a number of remotely located irrigation or sprinkler valves from a central location by means of control signals encoded onto a single pair of power transmission lines linking a central encoder and a number of remote decoders. The encoder includes a multiplexer for selecting on/off signals supplied by a controller, an address generator to drive the multiplexer and to generate decoder addresses for transmission, and coupling circuitry to encode the generated decoder addresses and on/off signals onto an alternating-current power signal, by clipping half-portions of the signal to represent zero values. Each decoder includes a bridge rectifier, from which clock pulses and a serial data stream are derived. The data stream is continually shifted through a shift register, and a comparator compares a decoder address field in the register with the conditions of a set of manual switches indicative of the decoder address.

Abstract: A device intended to receive two or more electrical conductors of the same or dissimilar size and to provide mechanical protection and electrical insulation for the electrical connection of said conductors, including a container for receiving the joined ends of the electrical conductors, the device including having side walls, a closed end wall and an open end and a plug member adapted to seal the open end of the casing. Passages are provided in the plug end or closed end for the extension therethrough of the electrical conductors. Cooperating locking means are provided on the plug and the casing member for mechanically interlocking the plug end casing and radial flaps are disposed in the passages which are deformed by the extension therethrough of the electrical conductor to define a cone shaped collar between the passage wall and the condutor to impede the flow of potting compound out of the device.