Isolated Sensor Interface Using Modulated Clock Signals
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Solution Overview
Problem
In measurement systems, the transmission of analog measurement signals over long distances is prone to distortion and noise, and harsh electrical conditions can vary wildly, requiring effective communication across electrical barriers while maintaining signal integrity.
Innovation Solution
A method and interface for communication between sensor units and control units in measurement systems, where the sensor unit's analog-to-digital converter is biased to a sensor reference voltage, and the control unit operates at a stable reference voltage, using modulated clock signals to convey control information across the interface, reducing the number of communication lines needed and enhancing signal robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If analog measurement signals are transmitted over long distances, then the measurement range is extended, but the signal quality deteriorates due to distortion and noise
Solution Approach 1:
An isolated interface circuit is introduced as an intermediary between the sensor unit and control unit. This interface circuit converts signals at the barrier and provides electrical isolation, allowing long-distance transmission while maintaining signal integrity by preventing noise and distortion from affecting the measurement signal throughout the entire transmission path.
Solution Approach 2:
The patent replaces direct electrical connection with optical or magnetic coupling across the barrier. By using light or magnetic fields instead of direct electrical conductors to cross the barrier, the system achieves long-distance transmission with improved signal quality, as these fields are less susceptible to electromagnetic interference and signal degradation.
2Reliability
If electrical barriers are introduced to separate sensor units from control units in harsh conditions, then the reliability of the control unit is improved, but the complexity of the communication interface increases
Solution Approach 1:
Multiple functions are merged into the isolated interface circuit: signal conversion, electrical isolation, and control information transmission all occur within a single integrated circuit. This consolidation reduces overall system complexity despite the presence of the barrier, as the interface circuit handles multiple tasks that would otherwise require separate components.
Solution Approach 2:
The isolated interface circuit is designed as a universal component that can handle various signal types and communication protocols while providing electrical isolation. This multi-functional design reduces the need for specialized components for different harsh condition scenarios, simplifying the overall system architecture despite the presence of the barrier.
3Measurement precision
If multiple communication lines are used to transmit control information across the barrier, then the control precision is improved, but the device complexity increases
Solution Approach 1:
Multiple control information signals are merged into a single communication line by modulating them onto a clock signal. This allows precise transmission of control information while reducing the number of physical communication lines needed, as multiple data streams share the same transmission medium through time-division or frequency-division multiplexing.
Solution Approach 2:
The patent changes the parameter of the clock signal (frequency, duty cycle, or phase) to encode control information. By varying these parameters, multiple control commands can be transmitted through a single line with high precision, avoiding the need for multiple separate communication lines while maintaining accurate control signal transmission.
Data Source
AI summary
Methods for use in a measurement system. Some embodiments comprise at least one sensor unit and a control unit, wherein the at least one sensor unit is configured to detect a physical quantity and to form a sensor data signal. The method comprises, at the control unit, receiving a data receive signal from the sensor unit, and interpreting the data receive signal to be one of at least the sensor data signal and another data signal, wherein the interpreting is based on an attribute information intrinsic to the data receive signal. Furthermore, there is a sensor unit for use in measurement data acquisition, an apparatus configured to control a measurement data acquisition, a measurement system for use in measurement data acquisition, and a medium incorporating a sequence of operation steps that, when executed, perform a method for use in a measurement system for data acquisition.