Transmitter Current Range Setting for Low-Power 4-20 mA Loops
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Solution Overview
Problem
The existing 4-20 mA current output range for instrumentation signals is a global standard, making it difficult to achieve low-power operation in two-wire transmitters used in manufacturing plants, and variations in installation timing or manufacturer can lead to operational errors.
Innovation Solution
A setting device and method that allows for a low-current mode with adjustable current and voltage settings, enabling the use of a second current output range smaller than the standard 4-20 mA range, and includes a communication unit for digital communication and voltage adjustment to ensure compatible operation between input-output devices and two-wire transmitters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the standard 4-20 mA current output range is used for instrumentation signals, then compatibility and reliability are ensured, but electrical power consumption cannot be reduced
Solution Approach 1:
The transmitter is designed to dynamically switch between standard mode (4-20 mA) and low-current mode based on communication results. The system adapts its current output characteristics from a fixed standard range to a variable range that can operate at lower currents when power reduction is needed, while maintaining compatibility through dynamic adaptation rather than static design
Solution Approach 2:
The patent changes the current output parameters from the fixed standard range of 4-20 mA to an adjustable range that can operate at lower current values. By modifying the electrical parameter (current magnitude) while maintaining the communication protocol and operational framework, the system achieves power reduction without completely abandoning the standard
2Use of energy by moving object
If a second current output range smaller than 4-20 mA is introduced, then power consumption is reduced, but compatibility and operational reliability may be compromised
Solution Approach 1:
The system employs communication feedback between the setting device and transmitter to determine whether the second current output range is successfully obtained. Based on this feedback, the setting device automatically selects the appropriate current output range, ensuring that power reduction modes are only activated when both devices support them, thus maintaining operational reliability
Solution Approach 2:
The system dynamically adapts between standard and low-current modes based on mutual capability verification. The transmitter and setting device communicate to determine compatibility, then dynamically adjust operating parameters accordingly, ensuring reliability is maintained through adaptive rather than static operation
3Ease of operation
If automatic setting based on communication is implemented, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The setting device automatically configures the transmitter by communicating to obtain the second current output range and autonomously determining the appropriate current output setting. This self-service approach eliminates manual configuration requirements, and the communication complexity is justified by the automation benefit, as the system performs the complex task automatically without user intervention
Data Source
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AI summary
A setting device 10 includes a communication unit 11 configured to perform communication for obtaining a second current output range which represents a current output range of a transmission signal passing via a loop formed between a transmitter that converts a physical quantity into a current value and an input-output device that outputs a current value input from the transmitter to a system and which has minimum current value or maximum current value to be smaller than a first current output range, and a setting unit 15 configured to set current output corresponding to either the first current output range or the second current output range based on whether or not the second current output range is successfully obtained.