Parallel HART Communication Module for Loop-Powered Diagnostics
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Solution Overview
Problem
Existing process automation systems face challenges in retrofitting to obtain diagnostic data from field devices with minimal installation effort, as current methods are costly and complex, requiring separate energy supplies and disrupting system operations.
Innovation Solution
A communication module that harnesses energy from the existing 4-20mA current loop or uses energy harvesting to query and transmit diagnostic data via HART protocol, allowing for wireless transmission using low-power technologies like Bluetooth LE, and integrates with the control station without interrupting the communication loop, enabling efficient data collection and processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If additional components are installed to enable digital communication with field devices, then diagnostic data can be read out, but installation effort and costs increase significantly
Solution Approach 1:
A communication module is introduced as an intermediary component that connects to the existing 4-20mA communication loop and enables HART protocol communication. This module acts as a mediator between the field device and the higher-level unit, allowing diagnostic data extraction without requiring direct integration into the field device or complete system redesign.
Solution Approach 2:
The communication module is designed to work with both 4-20mA analog communication and HART digital communication protocols through a single device. It can extract diagnostic data from HART-modulated signals while passing through the analog current signal, providing multi-functional capability in one component that reduces the need for separate communication infrastructure.
2Loss of information
If additional components are installed to enable digital communication, then diagnostic data can be obtained, but system operations must be interrupted
Solution Approach 1:
The communication module is designed to be installed in parallel with the existing communication loop, allowing it to tap into the HART signals without interrupting the 4-20mA current flow. This enables continuous operation of the process control system while diagnostic data is being extracted and transmitted to the higher-level unit.
3Loss of information
If additional components are installed to enable digital communication, then diagnostic data can be read out, but power supply requirements increase
Solution Approach 1:
The communication module is designed to be powered directly from the 4-20mA communication loop it connects to. It harvests energy from the existing current signal to operate its electronics and wireless transmission, eliminating the need for separate power supply connections or battery installations. This self-powered approach reduces installation complexity and avoids additional power infrastructure requirements.
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 simple and efficient retrieval of diagnostic data from field devices with reduced installation effort and energy requirements, maintaining measurement accuracy and allowing real-time data availability at the control center.
Implementation Method 1
A communication module that harnesses energy from the existing 4-20mA current loop or uses energy harvesting
Implementation Method 2
Many of these field devices can be parameterized via the HART protocol by modulating a digital signal onto the direct current using an FSK (Frequency Shift Keying) modem
Data Source
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Figure 2
AI summary
The invention comprises a method, a communication module (KM1, KM2) and a system for transmitting diagnosis data of a field device (FG1, FG2) in an installation for process automation, wherein the field device (FG1, FG2) has a communication link to a superordinate unit (SPS) via a communication loop (KS1, KS2) and wherein a communication module (KM1, KM2) is connected to the communication loop (KS1, KS2) such that the communication module (KM1, KM2) is connected in parallel with the field device (FG1, FG2), comprising: – continual storage of electric power in an energy storage unit (EE) of the communication module by means of a transducer unit (WE) connected upstream of the energy storage unit (EE) up to a predetermined limit value, wherein the transducer unit (WE) captures an electrical and/or physical variable and converts it into electric power; – polling of the diagnosis data of the field device (FG1, FG2) by a communication command by means of the communication module (KM1, KM2); – reception of the diagnosis data of the field device (FG1, FG2) by the communication module (KM1, KM2) by means of a communication command sent by the field device and wireless transmission of the polled diagnosis data to a reception unit (GW) by means of the communication module (KM1, KM2) as soon as the electric power stored in the energy storage unit (EE) reaches, or has exceeded, the predetermined limit value and/or if the communication module (KM1, KM2) receives a command for polling or transmitting.