Variable Voltage Drop RF Adapter for Two-Wire Process Control Loops
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Solution Overview
Problem
In industrial process control systems, traditional two-wire process control loops limit the power availability to field devices due to fixed voltage drops, which can affect the operation of wireless adapters and reduce communication efficiency.
Innovation Solution
A wireless adapter with variable voltage drop circuitry that adjusts power supply based on loop current, using a regulator and shunt circuitry to maintain sufficient power for wireless communication while minimizing voltage drop during high current conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed voltage drop is maintained across the RF adapter terminals, then the adapter can operate with simple circuitry, but the power available to the adapter is limited and cannot adapt to varying loop current conditions
Solution Approach 1:
The patent implements a dynamic voltage drop mechanism where the voltage across the RF adapter terminals varies based on the loop current magnitude. A controller monitors the loop current and adjusts the voltage drop accordingly - maintaining a higher voltage drop when current is low to maximize power availability, and reducing the voltage drop when current is high to preserve power for the field device. This dynamic adjustment resolves the contradiction by making power availability adaptive rather than fixed.
Solution Approach 2:
The patent changes the electrical parameter (voltage drop) of the RF adapter based on operating conditions. By varying the voltage drop parameter in response to loop current measurements, the system optimizes power distribution between the adapter and field device. This parameter change allows the adapter to extract maximum available power under varying current conditions without requiring complex external power supply circuitry.
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
The solution ensures consistent power supply to field devices, enhancing wireless communication efficiency and reliability by optimizing power usage across varying current levels in the process control loop.
Implementation Method 1
A regulator having a regulator input is coupled to the first terminal and an output
Implementation Method 2
Shunt circuitry is coupled to the output of the regulator and is configured to provide power to the wireless communication circuitry
Implementation Method 3
A feedback circuit is configured to control current flowing from the regulator to the shunt circuitry as a function of a loop current flowing through the two-wire process control loop
Data Source
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AI summary
A wireless adapter for use in a two- wire process control loop (22) includes wireless communication circuitry and first and second terminals configured to couple in series with the two-wire process control loop (22). A regulator (152) having a regulated input is coupled to the first terminal and an output. A shunt (154) is coupled to the output of the regulator (152) and is configured to provide power to the wireless communication circuitry. A feedback circuit (158) is configured to control current flowing from the regulator (152) to the shunt (154) as a function of a loop current flowing through the two- wire process control loop (22).