Bidirectional Signal Isolation Circuit for Universal Industrial Signals
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Solution Overview
Problem
The configuration of various safe barriers through a multi-path circuit to distinguish and isolate transmission signals in industrial control systems increases cost and compromises applicability, leading to system instability due to signal interference.
Innovation Solution
A bidirectional transmission circuit comprising a power supply module, intrinsically safe energy limiting module, signal coupling modules, and isolation transformer module, along with a control module, to convert and isolate signals, enhancing anti-interference capability while reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple safe barriers are configured through multi-path circuits to distinguish and isolate transmission signals, then signal isolation and anti-interference capability are improved, but system cost and device complexity increase
Solution Approach 1:
The patent combines multiple signal transmission paths (control signals and universal signals) into a single bidirectional transmission circuit. The isolation transformer module handles both control signals from the control module and universal signals from field devices through the same isolated path, eliminating the need for separate multi-path circuits while maintaining signal isolation capability.
Solution Approach 2:
The bidirectional transmission circuit is designed to handle multiple types of signals (control signals and universal signals including 4-20mA and 0-10V analog signals, and digital on/off signals) through a unified structure. The signal coupling modules and isolation transformer module work together to process different signal types bidirectionally, making the circuit universal and multi-functional rather than requiring dedicated circuits for each signal type.
2Reliability
If multiple safe barriers are configured through multi-path circuits to distinguish and isolate transmission signals, then signal isolation and anti-interference capability are improved, but system cost increases
Solution Approach 1:
The patent merges the functions of multiple separate safe barriers into a single integrated bidirectional transmission circuit. By using one isolation transformer module and shared signal coupling modules, the system achieves the same isolation effect as multiple separate barriers would provide, but with reduced component count and lower overall cost.
Solution Approach 2:
The unified bidirectional transmission circuit can handle multiple signal types and transmission directions simultaneously, replacing what would traditionally require multiple specialized isolation barriers. This universality reduces the total number of components needed and lowers system cost while maintaining comprehensive signal isolation capability.
3Ease of manufacture
If conventional signals and PLC/DCS signals are transmitted bidirectionally without isolation, then system cost is reduced, but signal interference occurs and system stability deteriorates
Solution Approach 1:
The isolation transformer module acts as an intermediary between the control module and field devices, providing galvanic isolation while allowing bidirectional signal transmission. This intermediary component blocks interference and ground loops between the control system and field devices, maintaining system stability without requiring expensive multi-path isolation circuits.
Solution Approach 2:
The signal coupling modules convert signal parameters between different domains (current signals to voltage signals, different impedance levels) while the isolation transformer maintains isolation. This parameter conversion allows compatible bidirectional communication between control modules and diverse field devices at reduced cost while preventing signal interference through proper impedance matching and isolation.
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
The circuit achieves stable and reliable bidirectional signal transmission, improving anti-interference performance and reducing production costs, thereby enhancing the applicability of the control system.
Implementation Method 1
the isolation transformer module is configured to transmit the first alternating current signal to the second signal coupling module in an isolation manner
Data Source
AI summary
A bidirectional transmission circuit for a universal signal, comprising an intrinsically safe energy limiting module, a first signal coupling module, an isolation transformer module, a second signal coupling module and a control module; the first signal coupling module adjusts a first direct current signal of a universal signal to a first alternating current signal, the isolation transformer module transmits the first alternating current signal to the second signal coupling module in an isolation manner, and the second signal coupling module adjusts the first alternating current signal to a second direct current signal to a universal signal receiving terminal; the second signal coupling module further adjusts a third direct current signal of a control signal to a second alternating current signal, and the first signal coupling module further adjusts the second alternating current signal to a fourth direct current signal to a control signal receiving terminal.