Vacuum Gauge Nonvolatile Memory Calibration and Data Logging
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Solution Overview
Problem
Combination vacuum gauges face inaccuracies in vacuum measurements due to generic calibration practices that do not account for unique correction factors and interactions between sensors, leading to temperature gradient effects on heat-sensitive sensors, and difficulties in diagnosing malfunctions or failures without specific operating conditions.
Innovation Solution
Incorporating nonvolatile memory to store temperature compensating calibration parameters for heat-sensitive sensors, allowing for unique calibration data storage and retrieval, and logging measurement data to diagnose issues, which can be integral to the sensors or controller, enabling field replacement and improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If generic correction factors are used for calibration, then manufacturing complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent applies preliminary action by performing individual sensor calibration and interaction factor determination at the factory before the gauge reaches the user. Unique correction factors and temperature gradient compensation parameters are pre-calculated for each sensor combination, stored in memory, and automatically applied during operation, eliminating the need for complex user calibration while ensuring high measurement precision.
2Device complexity
If temperature gradient effects are ignored, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent applies parameter changes by introducing temperature gradient compensation parameters that account for thermal effects on heat-sensitive sensors. The system determines correction factors at multiple temperatures, calculates temperature gradients within the gauge housing, and applies compensation algorithms to adjust sensor readings, thereby maintaining measurement precision despite thermal variations.
3Device complexity
If operational data is not stored, then device complexity is reduced, but ease of repair deteriorates
Solution Approach 1:
The patent applies feedback by implementing a data logging system that continuously records operational parameters, sensor readings, and environmental conditions in non-volatile memory. When a malfunction occurs, this stored data provides feedback about the gauge's state before failure, enabling manufacturers to diagnose issues remotely and guide field repairs without requiring the gauge to be returned to the factory.
4Ease of operation
If field replacement is enabled without unique calibration data, then ease of operation is improved, but measurement precision deteriorates
Solution Approach 1:
The patent applies segmentation by separating the vacuum gauge into modular components with unique calibration data stored in memory modules or integrated circuits. Each sensor assembly can be independently replaced in the field, and the associated calibration data travels with the component, ensuring that measurement precision is maintained after replacement without requiring recalibration.
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 solution enhances measurement accuracy by accounting for sensor interactions and temperature gradients, and facilitates troubleshooting of malfunctions by storing operational data, allowing for more precise calibration and easier maintenance.
Implementation Method 1
there are temperature gradients that affect the heat-loss sensor temperature compensating equations
Implementation Method 2
A significant source of temperature variation in a combination vacuum gauge is the heat generated by the ionization gauge filament
Implementation Method 3
the heat-loss sensor interacts thermally with the ionization gauge
Data Source
AI summary
A method and apparatus for measuring gas pressure by combining an ionization gauge with at least one other vacuum sensor. Nonvolatile memory coupled to the vacuum gauge contains calibration parameters unique to each individual sensor based on factory calibration. The nonvolatile memory may contain calibration parameters for a heat-sensitive vacuum sensor to compensate for the temperature gradients generated by the ionization gauge. The calibration parameters are a function of calibration data determined when the ionization gauge is both on and off. The nonvolatile memory may store a window of measurement data of the vacuum gauge that is updated at predetermined time intervals and in response to an event, such as an error event, to aid in investigating the cause of vacuum gauge malfunction or failure.