Two-wire controlling and monitoring system for irrigation of localized areas of soil

• US 6,766,221 B1
• Filed: 11/22/2000
• Issued: 07/20/2004
• Est. Priority Date: 11/25/1999
• Status: Expired due to Term

• Current Assignee: S-Rain Control A/S
• Original Assignee: S-Rain Control A/S
• Inventors: Christiansen, Tom Nøhr
• Primary Examiner(s): RODRIGUEZ, PAUL L
• Application Number:
  US09/721,461
• Time in Patent Office: 1,336 Days
• Field of Search: 700/284.3, 700/9, 700/19, 700/22, 700/282, 700/283, 340/310.01, 340/310.02, 239/63, 239/67, 239/69, 137/78.2, 137/624.11, 137/624.12, 137/624.18, 137/624.22
• US Class Current: 700/284
• CPC Class Codes: A01G 25/16 Control of watering
• CPC Class Codes: A01G 25/167 Control by humidity of the soil itself or of devices simulating soil or of the atmosphere; Soil humidity sensors
• CPC Class Codes: Y10T 137/1866 For controlling soil irrigation
• CPC Class Codes: Y10T 137/86389 Programmer or timer

Abstract

A two-wire controlling and monitoring system for in particular irrigation of localized areas of soil according to a aspect of the invention comprises a water pipeline, a first plurality of controllable irrigation valves, a second plurality of field sensors measuring specific irrigation parameters, and a third plurality of localized irrigation control units. The third plurality of localized irrigation control units each comprises a sensor decoder connected to a specific field sensor of the second plurality of field sensors and/or a line decoder connected to a specific controllable irrigation valve of the first plurality of controllable irrigation valves. The two-wire controlling and monitoring system further comprises a controller and power supply unit having a set of schedules of instructions and supplying power by applying a first alternating DC voltage signal to a two-wire cable interconnecting the controller and power supply unit and the third plurality of localized irrigation control units. The two-wire cable provides the power from the controller and power supply unit to each of the third plurality of localized irrigation control units. The controller and power supply unit transmits the schedules of instructions to the third plurality of localized irrigation control units through the two-wire cable and receives the specific irrigation parameters from the third plurality of localized irrigation control units through the two-wire cable.

Claims

1. A two-wire controlling and monitoring system for in particular irrigation of localized areas of soil and comprising:

a water pipeline providing water to said localized areas of soil,

a first plurality of controllable irrigation valves each positioned at a specific area of said localized areas of soil, communicating with said water pipeline, providing watering or non-watering of said specific area of said localized areas of soil and having a pair of valve control inputs,

a second plurality of field sensors positioned at specific areas of said localized areas of soil, providing specific irrigation parameters and having a pair of sensor outputs,

a third plurality of localized irrigation control units each comprising a sensor decoder having a pair of sensor inputs connected to said pair of sensor outputs of a specific field sensor of said second plurality of field sensors for providing power to said second plurality of field sensors and recording said specific irrigation parameters from said second plurality of field sensors and a line decoder having a pair of valve control outputs connected to said pair of valve control inputs of a specific controllable irrigation valve of said first plurality of controllable irrigation valves for providing valve control signals to said first plurality of controllable irrigation valves, said sensor decoder and said line decoder further each having a pair of control and power supply inputs,

a controller and power supply unit having a set of schedules of instructions and having a pair of control and power outputs supplying power by applying a first alternating DC voltage signal defining a voltage maximum having a first pulse width and defining a voltage minimum having a second pulse width to one of said pair of control and power outputs, simultaneously applying a second alternating DC voltage signal of inverted polarity as compared to said first alternating DC voltage signal to another of said pair of control and power outputs, said second alternating DC voltage signal defining a voltage maximum having a pulse width equal to said first pulse width and defining a voltage minimum having a pulse width equal to said second pulse width, and applying an alternating DC current defining a current maximum having a third pulse width and defining a current minimum having a fourth pulse width to said pair of control and power outputs, wherein said first and second alternating DC voltage signals alternate with a frequency of less than 50 Hz,

a two-wire cable interconnecting said controller and power supply unit and said third plurality of localized irrigation control units and connecting said pair of control and power outputs of said controller and power supply unit to said control and power inputs of said third plurality of localized irrigation control units and providing said power from said controller and power supply unit to each of said third plurality of localized irrigation control units, and

said controller and power supply unit transmitting said schedules of instructions to said third plurality of localized irrigation control units through said two-wire cable and receiving said specific irrigation parameters from said third plurality of localized irrigation control units through said two-wire cable.

2. The two-wire irrigation controlling and monitoring system according to claim 1, wherein said water pipeline is wholly or partly buried under ground, or said water pipeline is placed on the ground and/or wherein said water pipeline are constructed from plastic materials or metal materials such as iron, steel, copper, silver, gold or any alloys thereof in any combinations thereof.

3. The two-wire irrigation controlling and monitoring system according to claims 1 or 2, wherein said first plurality of controllable irrigation valves are operated by a mechanism that is selected from the group consisting of a magnetic mechanism, an electrical mechanism, a hydraulic mechanism, a pneumatic mechanism, and any combination of the aforesaid mechanisms, wherein said first plurality of controllable irrigation valves are opened by applying an inrush signal followed by a hold signal to said pair of valve control inputs and closed by applying a zero signal to said pair of valve control inputs, and wherein said second plurality of field sensors comprises sensors selected from the group consisting of temperature sensors, humidity sensors, pressure sensors, flow sensors, magnetic field sensors, mechanical movement sensors, mechanical strain sensors, fertilizer sensors and any combination of the aforesaid sensors.

4. The two-wire irrigation controlling and monitoring system according to claim 3, wherein said line decoder provides said inrush signal, said hold signal and said zero signal to said first plurality of controllable irrigation valves by supplying from said pair of valve control outputs a pulsed alternating DC control signal to said pair of valve control inputs in accordance with said transmitted schedules of instruction, and wherein said pulsed alternating DC control signal defining a maximum voltage in the range of 25V to 45V and a minimum voltage in the range of 0V to 5V, said line decoder output pulse width defining a first part having said maximum voltage and a second part having said minimum voltage, and wherein said pulsed alternating DC control signal constituting said inrush signal, by having said first part longer than or equal to said second part during a period in the range 10 ms to 1 s and constituting said hold signal and by having said first part shorter than said second part during a period determined in accordance with said schedule of instructions transmitted to said line decoders by said controller and power supply unit.

5. The two-wire irrigation controlling and monitoring system according to claims 1 or 2, wherein said first pulse width, relative to said second pulse width, is selected from the group consisting of equal to said second pulse width, smaller than said second pulse width, greater than said second pulse width.

6. The two-wire irrigation controlling and monitoring system according to either claims 1 or 2 wherein at least one of said first and second pulse widths of said first alternating DC voltage signal and said second alternating DC voltage signal is in the range 100 ms to 10 s.

7. The two-wire irrigation controlling and monitoring system according to either claims 1 or 2 wherein said voltage maximum is in a range from +10V to +20V, and wherein said voltage minimum is in a range from −

15V to −

25V.

8. The two-wire irrigation controlling and monitoring system according to claims 1 or 2, wherein said first alternating DC voltage signal and said second alternating DC voltage signal during said first pulse width and said second pulse width have an average voltage in the range −

5V to −

0.5V.

9. The two-wire irrigation controlling and monitoring system according to claims 1 or 2 wherein said current maximum is in the range of 0.5 A to 2 A, and wherein said current minimum is in the range 20 Ma to 150 Ma.

10. The two-wire irrigation controlling and monitoring system according to claims 1 or 2, wherein said third pulse width is greater than said fourth pulse width, and wherein said fourth pulse, width is in the range 0.1 ms to 10 ms.

11. The two-wire irrigation controlling and monitoring system according to claims 1 or 2 wherein said schedules of instructions are transmitted onto said two-wire cable by re-scaling one of said first pulse width and said second pulse width to one of a first re-scaled pulse width in the range 10 ms to 49 ms indicating a binary “

1” and

a second re-scaled pulse width in the range 0.1 ms to 9 ms indicating a binary “

0”

, and wherein said schedules of instructions comprise a type of declaration determining additional content of a transmission from said controller and power supply unit to said third plurality of localized irrigation control units, said additional content being selected from the group consisting of an address of a specific designated localized irrigation control unit of said third plurality of localized irrigation control units, data disclosing information regarding actions to be taken by said specific designated localized irrigation control unit of said third plurality of localized irrigation control units, and a first check and a second check ensuring a safe reception of said transmission, wherein said transmission is terminated by a stop signal having a stop signal pulse width in the range of 50 ms to 70 ms.

12. The two-wire irrigation controlling and monitoring system according to claim 11, wherein said type of declaration comprises 4 bits and provides 16 optional operations selected from the group consisting of Arbitration, Data, Control (On/Off), Broadcast, Test, and Pole;

wherein said address of said specific designated localized irrigation control unit of said third plurality of localized irrigation control units comprises an address transmission size in the range 0 to 128 bits;

wherein said data disclosing information regarding actions to be taken by said specific designated localized irrigation control unit of said third plurality of localized irrigation control units comprises a data transmission size in the range of 0 to 64 KBYTE; and

wherein said first check and said second check ensuring a safe reception of said transmission comprise a check transmission size in the range of 0 to 128 bits.

13. The two-wire irrigation controlling and monitoring system according to claims 1 or 2, wherein a differential voltage is created in said two-wire cable, and wherein said controller and power supply unit comprises:

a microprocessor;

a storage unit for storing said schedules of instructions;

an output section for providing power to said two-wire cable and transmitting said schedules of instructions on said two-wire cable; and

an input section for monitoring the voltage of said two-wire cable;

wherein said microprocessor controls said output section to apply said current minimum to said two-wire cable during an interrupt window;

wherein each of said sensor decoders and line decoders comprises a short circuiting circuit providing (1) an interrupt signal during said interrupt window to said controller and power supply unit by unidirectionally short circuiting said pair of control and power supply inputs, thereby reducing the differential voltage of said two-wire cable, and (2) a no interrupt signal by open circuiting said pair of control and power supply inputs, wherein said interrupt signal is constituted by a voltage drop of said differential voltage of said two-wire cable in the range of 5V to 35V; and

wherein said interrupt window is initiated following a DC alternation of said first alternating DC voltage signal and said second alternating DC voltage signal and a power supply period in the range of 250 ms to 550 ms, wherein said interrupt window is in the range of 0 to 20 ms.

14. The two-wire irrigation controlling and monitoring system according to claim 13, wherein said microprocessor records said interrupt signal from at least one of said sensor decoders and line decoders of said third plurality of said localized irrigation control units through said input section monitoring voltage of said two-wire cable, and subsequently operates said output section to perform a DC alternation of said first alternating DC voltage signal and said second alternating DC voltage signal, and operates said output section to terminate said interrupt window and to apply said current maximum to said two-wire cable;

and

wherein said microprocessor, following a recording of said interrupt signal from at least one interrupting decoder selected from the sensor decoders and the line decoders of said third plurality of localized irrigation control units, performs a DC alternation of said first alternating DC voltage signal and said second alternating DC voltage signal, and transmits a type declaration providing an Arbitration operation followed by a series of binary “

1”

s, including an answer window for said at least one interrupting decoder to answer to said binary “

1”

s; and

wherein said answer window is initiated following a DC alternation of said first alternating DC voltage signal, said second alternating DC voltage signal, and a pause period in the range of 2 ms to 10 ms, whereby said answer window is in the range of 0 to 20 ms.

15. The two-wire irrigation controlling and monitoring system according to claim 14, wherein said short circuiting circuit provides (1) an answer signal during said answer window to said controller and power supply unit by unidirectionally short circuiting said pair of control and power supply inputs, thereby reducing the differential voltage of said two-wire cable, and (2) a no answer signal by open circuiting said pair of control and power supply inputs;

and wherein said answer signal is constituted by a voltage drop in said differential voltage of said two-wire cable in the range of 5V to 35V; and

wherein said microprocessor controls said output section to supply said current minimum to said two-wire cable during said answer window.

16. The two-wire irrigation controlling and monitoring system according to claim 15, wherein said controller and power supply unit, during a declared type of transmission of schedules of instructions, requests said specific irrigation parameters from an addressed sensor decoder of said third plurality of localized irrigation control units, and subsequently said controller and power supply unit transmits a series of binary “

1”

s, including said answer window, for said addressed sensor decoder to answer said binary “

1”

s; and

wherein said microprocessor (1) records said answer signal from at least one sensor decoder of said third plurality of localized irrigation control units by using said input section to monitor said differential voltage of said two-wire cable, and (2) operates said output section to perform a DC alternation of first alternating DC voltage signal and said second alternating DC voltage signal and (3) subsequently operates said output section to terminate said answer window and to apply said current maximum to said two-wire cable; and

wherein said microprocessor interprets said answer signal as a binary “

0” and

a no answer signal as a binary “

1”

.