Redundant Power-Line Telegram Transmission for Safety Controllers
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Solution Overview
Problem
Industrial automation systems require secure, long-distance communication for safety-critical applications, but existing methods like PROFIBUS DP rely on complex protocols, which can be cumbersome and inefficient, especially for modular safety controllers and field devices located outside control cabinets.
Innovation Solution
A method and adapter system utilizing carrier frequency technology to modulate redundant data telegrams onto different lines of a power supply, leveraging the architecture of power supply systems with multiple lines to create independent signal channels, and employing OFDM for high data rates, ensuring secure and reliable communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex protocols like PROFIBUS DP are used for secure data transmission, then functional safety requirements are met, but device complexity and cabling effort increase
Solution Approach 1:
The data transmission is segmented into two independent redundant channels, each carrying a separate version of the data telegram. This segmentation allows the system to meet functional safety requirements through physical redundancy rather than complex protocol layers, simplifying the overall device complexity while maintaining reliability.
Solution Approach 2:
The invention creates redundant copies of the data telegram and transmits them via different power supply lines. This copying approach provides the necessary redundancy for functional safety without requiring complex safety protocols, thereby reducing device complexity while ensuring reliable transmission.
2Reliability
If separate data lines are used for field devices, then communication reliability is ensured, but cabling effort and installation complexity increase
Solution Approach 1:
The invention merges data transmission with the existing power supply lines by modulating data onto the voltage between power supply conductors. This eliminates the need for separate data cables, significantly reducing cabling effort and installation complexity while maintaining communication reliability through the redundant power supply lines.
Solution Approach 2:
The power supply lines are given dual functionality: they simultaneously provide electrical power to field devices and serve as communication channels for data transmission. This multi-functionality eliminates the need for dedicated data cables, reducing installation complexity while ensuring reliable communication through the existing robust power infrastructure.
3Ease of manufacture
If redundant data transmission channels are created using power supply lines, then cabling effort is reduced, but signal interference and transmission reliability may worsen
Solution Approach 1:
The redundant transmission channels are segmented across different power supply lines (e.g., different phases or conductors). This physical separation minimizes signal interference between channels while utilizing the existing power infrastructure, thereby reducing cabling effort without compromising transmission reliability.
Solution Approach 2:
The invention uses modulation as an intermediary technique to encode data onto the power supply voltage. This modulation process transforms digital data into analog signals that can be transmitted over power lines, enabling reliable communication through the power infrastructure while minimizing direct interference between channels through proper modulation schemes.
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
This approach simplifies secure data transmission by using hardware-based redundancy on the OSI layers 1 and 2, reducing complexity and cabling needs, while achieving high data rates and enabling effective error detection and preventive maintenance in industrial automation systems.
Implementation Method 1
the data telegram is modulated by the transmitter via a carrier frequency onto a voltage between two lines of the power supply
Implementation Method 2
demodulated again by the receiver
Data Source
Figure 1
Figure 2~3
AI summary
A method for the secure transmission of data telegrams between a transmitter (10, 20, 22, 24) and a receiver (10, 20, 22, 24) in accordance with a safety standard, wherein the transmitter (10, 20, 22, 24) and receiver (10, 20, 22, 24) are connected to a common power supply (28) and the data telegram is modulated by the transmitter (10, 20, 22, 24) via a carrier frequency onto a voltage between two lines of the power supply (28) and is demodulated again by the receiver (10, 20, 22, 24), is intended to allow the secure transmission of data telegrams in a technically particularly simple way.For this purpose, the transmitter (10, 20, 22, 24) provides two redundant versions of the data telegram, the power supply (28) comprises at least three lines, and the first version of the data telegram is modulated onto a voltage between a first line and a second line of the power supply (28), and the second version of the data telegram is modulated onto a voltage between a third line and any further line of the power supply (28).