Multi-Wire Irrigation Signal Modulation With Solenoid Current Feedback
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Solution Overview
Problem
Existing irrigation control systems using a two-wire path for power and data transmission face inefficiencies in data modulation and solenoid activation, particularly in determining proper operation and detecting ground short conditions, due to limitations in current measurement and data decoding methods.
Innovation Solution
The system employs an encoder that converts AC power to DC voltage, generates an AC signal modulated with data using techniques like frequency or amplitude modulation, and includes a decoder unit with a current measurement circuit to determine solenoid operation and detect ground shorts, ensuring accurate data transmission and solenoid activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If AC power signal is modulated by selectively clipping the positive half signal, then data can be transmitted to decoders, but the system cannot reliably detect ground short conditions or determine proper solenoid operation
Solution Approach 1:
The patent introduces a current measurement circuit as an intermediary component between the modulated signal source and the decoder. This circuit measures the current drawn by the solenoid and provides feedback information about actual solenoid operation and ground short conditions, enabling reliable detection without interfering with the data transmission modulation scheme
Solution Approach 2:
The system implements feedback by measuring the current drawn by the solenoid through a current measurement circuit and using this information to determine both proper solenoid operation and ground short conditions. The feedback loop allows the system to verify that data transmission is achieving the desired physical effect (solenoid activation) and to detect fault conditions
2Device complexity
If a two-wire path is used for power and data transmission, then system simplicity is maintained, but current measurement capabilities are limited
Solution Approach 1:
The patent makes the two-wire path multi-functional by using it simultaneously for power transmission, data transmission via modulation, and current measurement for solenoid verification and ground short detection. The current measurement circuit measures current flowing through the same two-wire path, extracting diagnostic information without requiring additional wiring
Solution Approach 2:
The system uses the existing current flow required for solenoid operation as the measurement signal itself. The current that powers the solenoid and carries the modulated data also provides the measurement information needed for verifying operation and detecting ground shorts, eliminating the need for separate measurement circuits or additional wires
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables reliable and efficient power and data transmission to irrigation devices, ensuring proper solenoid operation and detecting potential issues like ground shorts, thereby improving the overall control and reliability of irrigation systems.
Implementation Method 1
an AC to DC converter configured to convert an input AC signal into a DC voltage
Implementation Method 2
generates an AC output signal modulated with data; the data modulated on the AC output signal; encoding each cycle of the AC signal with one of two frequencies
Implementation Method 3
modulated with data using techniques like frequency or amplitude modulation
Data Source
AI summary
In some embodiments, apparatuses and methods are provided herein useful to providing power and data to an irrigation device. In some embodiments, encoder for an irrigation control unit that provides power and data to an irrigation device over a multi-wire path comprises: an AC to DC converter to convert an input AC signal into a DC voltage; an AC signal generator to generate an output AC signal modulated with data; a control circuit to provide a modulation control signal to the AC signal generator to control generation and modulation of the output AC signal, the data modulated on the output AC signal comprising commands in accordance with irrigation programming; and a multi-wire interface coupled to the AC signal generator to electrically couple to a multi-wire path extending into a landscape and to which irrigation devices may be connected.