Decoder systems and methods for irrigation control

1. An irrigation system implemented to power and selectively energize a plurality of solenoid-actuated valves connected to corresponding decoders along a two-wire communication network using data encoded power waveforms, the irrigation system comprising:

an irrigation controller comprising:

a first processor configured to communicate with a user input device, wherein the user input device is configured to accept user input from a user and output information responsive to the user input, the first processor configured to generate a control signal responsive to the information, the control signal having a first state and a second state; and

a first power supply configured to receive an input power signal, provide an AC power signal, and output the data encoded power waveforms to control the plurality of solenoid-actuated valves, wherein the AC power signal is approximately sinusoidal, the first power supply communicating with the first processor to receive the control signal, pass the AC power signal approximately in-phase when the control signal is in the first state and shift a phase of the AC power signal approximately by 180 degrees when the control signal is in the second state, the first power supply outputting the approximately in-phase AC power signal on the two-wire communication network when the control signal is in the first state and outputting the phase-shifted AC power signal on the two-wire communication network when the control signal is in the second state; and

at least one decoder configured to communicate with the two-wire communication network and at least one solenoid-actuated valve, the at least one decoder comprising:

a communication interface configured to extract a data portion from the data encoded power waveforms received from the two-wire communication network;

a second processor configured to receive the data portion from the communication interface and provide a solenoid control signal responsive to the data portion; and

a second power supply configured to communicate with the at least one solenoid-actuated valve, receive the data encoded power waveform from the two-wire communication network, and provide a solenoid power signal based on the data encoded power waveform, the second power supply comprising a switching circuit that is configured to receive the solenoid control signal and the solenoid power signal, and pass the solenoid power signal to the at least one solenoid-actuated valve responsive to the solenoid control signal.

2. The irrigation system of claim 1 wherein the switching circuit comprises a solid state relay.

3. The irrigation system of claim 1 wherein the switching circuit comprises a triode for alternating current.

4. The irrigation system of claim 1 wherein the switching circuit comprises a transistor.

5. The irrigation system of claim 4 wherein the switching circuit further comprises a freewheeling diode to conduct electromagnetic forces generated by the at least one solenoid-actuated valve when the transistor is off.

6. The irrigation system of claim 4 wherein the solenoid control signal turns the transistor on for approximately 300 microseconds and turns the transistor off for approximately 700 microseconds to control the at least one solenoid-actuated valve.

7. The irrigation system of claim 4 wherein the transistor is a MOSFET.

8. The irrigation system of claim 1 wherein the second power supply comprises a bridge circuit.

9. The irrigation system of claim 1 wherein the communication interface circuit comprises a comparator configured to receive the data encoded power waveform and generate the data portion.

10. The irrigation system of claim 1 wherein the at least one solenoid-actuated valve comprises a DC latching solenoid and wherein the second power supply comprises a capacitor that is configured to charge responsive to the solenoid control signal and an H-bridge circuit that is configured to deliver the charge to the DC latching solenoid responsive to the responsive to the solenoid control signal.

11. The irrigation system of claim 1 further comprising the two-wire communication network in communication with the irrigation controller and the at least one decoder.

12. The irrigation system of claim 11 further comprising a second two-wire communication network in communication with the irrigation controller and a decoder that is separate from the at least one decoder.

13. The irrigation system of claim 1 wherein the at least one decoder is configured to encode data onto the two-wire communication network for transmission to the irrigation controller.

14. The irrigation system of claim 1 wherein the at least one decoder is configured to draw modulated current to transmit messages over the two-wire communication network and the irrigation controller is configured to receive the messages by sensing the modulated current.

15. A method to power and selectively energize a plurality of solenoid-actuated valves connected to corresponding decoder circuits along a two-wire communication network using data encoded power waveforms, each decoder circuit serially addressable over the two-wire communication network and configured to energize its corresponding solenoid-actuated valves, the method comprising:

at an irrigation controller in communication with the two-wire communication network,

receiving information responsive to user input from a user device;

generating a control signal responsive to the information, the control signal having a first state and a second state;

providing an AC power signal that is approximately sinusoidal;

when the control signal is in the first state, pass the AC power signal approximately in-phase and output the approximately in-phase AC power signal on the two-wire communication network and when the control signal is in the second state, shift a phase of the AC power signal by approximately 180 degrees and output the phase-shifted AC power signal on the two-wire communication network to form the data encoded power waveforms that are responsive to the control signal;

at a decoder in communication with the two-wire communication network and at least one solenoid-actuated valve,

extracting a data portion from the data encoded power waveforms received from the two-wire communication network;

providing a solenoid control signal responsive to the data portion;

providing a solenoid power signal based on the data encoded power waveform; and

enabling a switching circuit responsive to the solenoid control signal to pass the solenoid power signal to at least one solenoid-actuated valve.

16. The method of claim 15 further comprising, at the decoder, receiving, at a bridge circuit, the data encoded power waveform and outputting, from the bridge circuit, the solenoid power signal.

17. The method of claim 15 wherein the at least one solenoid-actuated valve comprises a DC latching solenoid, the method further comprising, at the decoder, charging a capacitor responsive to the solenoid control signal and delivering the charge to the DC latching solenoid responsive to the solenoid control signal.

18. A decoder in communication with a two-wire communication network and at least one solenoid-actuated valve, the at least one decoder comprising:

a communication interface configured to extract a data portion from data encoded power waveforms received from the two-wire communication network, the data encoded power waveforms generated by an irrigation controller having a first processor in communication with a user input device, wherein the user input device is configured to accept user input from a user and to output information responsive to the user input, the first processor configured to generate a control signal responsive to the information, the control signal having a first state and a second state; and a first power supply configured to receive an input power signal and provide an AC power that is approximately sinusoidal, the first power supply communicating with the first processor to receive the control signal, pass the AC power signal approximately in-phase when the control signal is in the first state and shift a phase of the AC power signal approximately by 180 degrees when the control signal is in the second state, the first power supply outputting the approximately in-phase AC power signal on the two-wire communication network when the control signal is in the first state and outputting the phase-shifted AC power signal on the two-wire communication network when the control signal is in the second state;

a second processor configured to receive the data portion from the communication interface and provide a solenoid control signal responsive to the data portion; and

a second power supply in communication with the at least one solenoid-actuated valve and configured to receive the data encoded power waveform from the two-wire communication network and provide a solenoid power signal based on the data encoded power waveform, the power supply comprising a switching circuit that is configured to receive the solenoid control signal and the solenoid power signal, and pass the solenoid power signal to the solenoid-actuated valve responsive to the solenoid control signal.

19. The decoder of claim 18 wherein the second power supply comprises a bridge circuit.

20. The decoder of claim 18 wherein the at least one solenoid-actuated valve comprises a DC latching solenoid and wherein the second power supply comprises a capacitor that is configured to charge responsive to the solenoid control signal and an H-bridge circuit that is configured to deliver the charge to the DC latching solenoid responsive to the responsive to the solenoid control signal.