Isolated HART Interface Circuit for Bidirectional 4-20 mA Communication
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Solution Overview
Problem
Conventional communication connection apparatuses in industrial fields, such as those in petroleum, chemical, and natural gas, primarily use 4-20 mA analog current signals for single-function communication, lacking bidirectional interaction and exhibiting poor performance.
Innovation Solution
A HART circuit with a control interface, adjustable power supply module, first HART module, isolation module, and field interface, enabling bidirectional communication through signal modulation and isolation, allowing for diverse application scenarios and improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If 4-20 mA analog current signals are used for communication, then single-function communication is achieved, but bidirectional interaction is not possible
Solution Approach 1:
The HART circuit enables the communication system to perform multiple functions simultaneously. The same communication interface supports both traditional 4-20 mA analog current signals for single-function communication and HART protocol for bidirectional digital communication, making the system universal and multi-functional without requiring separate communication channels
2Productivity
If conventional communication connection apparatuses are used, then simple single-function communication is achieved, but performance is poor
Solution Approach 1:
The patent merges the analog communication path and digital communication path into a single HART circuit interface. The communication apparatus integrates both the analog signal processing components and the HART protocol processing components, allowing bidirectional communication to occur over the same physical connection used for traditional 4-20 mA signals, thereby improving performance without significantly increasing device complexity
3Adaptability or versatility
If bidirectional communication is implemented, then application scenarios are diversified, but signal transmission safety may be compromised
Solution Approach 1:
The HART circuit acts as an intermediary device between the control room and the field instrumentation. It receives analog current signals from the field device, processes them through the HART protocol, and transmits bidirectional digital communication. This intermediary function allows diversified application scenarios while maintaining signal transmission safety through standardized protocol handling and signal conditioning
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
Enables bidirectional communication between control rooms and production fields, enhancing the applicability and performance of HART circuits by supporting diverse application scenarios and ensuring safe, stable signal transmission.
Implementation Method 1
The adjustable power supply module is configured to output a first power signal to the control interface and, in response to the first control signal, modulate the first power signal into a first HART signal
Implementation Method 2
The isolation module is configured to isolate a signal from the first terminal of the isolation module and couple the isolated signal to a second terminal of the isolation module
Data Source
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AI summary
The present application discloses a HART circuit and a method for determining the state of the field interface thereof. The HART circuit includes a control interface, an adjustable power supply module, a first HART module, an isolation module, and a field interface. The first HART module is connected to the control interface. The first HART module is configured to generate a first control signal when receiving a first inquiry signal from the control interface. The adjustable power supply module is connected to the control interface and the first HART module. The adjustable power supply module is configured to output a first power signal to the control interface and, in response to the first control signal, modulate the first power signal into a first HART signal. A first terminal of the isolation module is connected to the control interface. The isolation module is configured to isolate a signal from the first terminal of the isolation module and couple the isolated signal to a second terminal of the isolation module. The field interface is connected to the second terminal of the isolation module.