Two-Wire Field Device Data Transmission via Voltage Modulation
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Solution Overview
Problem
Existing data transmission methods for automation field devices, such as HART protocol, require significant space and are costly due to the use of large and expensive components like FSK modems, which is undesirable for low-cost field devices.
Innovation Solution
A method using a two-wire line for both power supply and data transmission, where the supply voltage is modulated to produce a communication signal that is demodulated by the field device, and the output current is similarly modulated to transmit data back, eliminating the need for a modem and allowing for space-saving and cost-effective communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If HART protocol with FSK modem is used for data transmission, then bidirectional communication and flexible parameterization are achieved, but device cost and space requirements increase significantly
Solution Approach 1:
The patent extracts the communication signal from a separate dedicated channel and embeds it within the existing power supply voltage line. By modulating the supply voltage, the system eliminates the need for separate communication hardware (modems) while maintaining bidirectional data transmission capability. This extraction principle removes the bulky FSK modem components while preserving communication functionality.
Solution Approach 2:
The supply voltage line is made multi-functional by enabling it to serve both power supply and data transmission purposes simultaneously. Through voltage modulation and demodulation, the same two-wire line that provides power also carries communication signals, eliminating the need for separate communication channels and reducing overall device complexity and component count.
2Reliability
If FSK modem components are installed in each field device, then reliable bidirectional communication is achieved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive, complex FSK modem components with simple, inexpensive voltage modulation and demodulation circuitry. The modulation can be achieved through basic electronic components that are much cheaper than dedicated modem chips, making the field devices more cost-effective for mass production while maintaining communication reliability through the robust voltage-based signaling.
Solution Approach 2:
The patent substitutes the mechanical/electronic FSK modulation system with a simpler voltage-based communication system. Instead of using frequency-shift keying that requires complex modems, the system uses direct voltage modulation where logical states are represented by different voltage levels, eliminating the need for sophisticated signal processing hardware and reducing manufacturing costs.
3Reliability
If separate communication line is used for data transmission, then communication quality is maintained, but device space and wiring complexity increase
Solution Approach 1:
The patent merges the power supply function and data transmission function into a single communication channel (the two-wire line). By combining these functions, the system eliminates the need for separate communication wiring and reduces the space required for communication components while maintaining reliable data transmission through voltage modulation on the shared line.
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 efficient and cost-effective data transmission between field devices and communication boxes, allowing for flexible programming and parameterization without the need for expensive modem components, while also enabling additional functionalities like radio communication.
Implementation Method 1
spannungsmodulation der Versorgungsspannung des Feldgeräts durch die Kommunikationsschaltkreis, sodass ein erstes Kommunikationssignal erzeugt wird und die Versorgungsspannung das erste Kommunikationssignal aufweist
Implementation Method 2
Demodulation des ersten Kommunikationssignals von der an das Feldgerät via Zweidrahtleitung angelegten Versorgungsspannung, sodass das erste Kommunikationssignal von der Versorgungsspannung getrennt wird
Implementation Method 3
Strommodulation eines Ausgangsstroms des Feldgeräts durch das Feldgerät, sodass ein zweites Kommunikationssignal erzeugt wird und der Ausgangsstrom das zweite Kommunikationssignal aufweist
Implementation Method 4
Demodulation des zweiten Kommunikationssignals vom Ausgangsstrom durch die Kommunikationsschaltkreis, sodass das zweite Kommunikationssignal vom Ausgangsstrom getrennt wird
Data Source
AI summary
The present disclosure relates to a method for transferring data between an automation field device and a communication box, wherein the method comprises: voltage modulation of the supply voltage of the field device by the communication box such that a first communication signal is produced and the supply voltage has the first communication signal; demodulation of the first communication signal from the supply voltage applied to the field device by means of the two-wire line such that the first communication signal is separated from the supply voltage; current modulation of an output current of the field device by the field device such that a second communication signal is produced and the output current has the second communication signal; demodulation of the second communication signal from the output current by the communication box such that the second communication signal is separated from the output current.