Plant Control Emulator Synchronization for Pre-Change Output Prediction
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Solution Overview
Problem
Existing plant operation simulation systems cannot check the effect of changes in control logic on output values while the plant is in operation, making it difficult to predict potential sudden changes in output values due to adjustments in control functions.
Innovation Solution
A plant operation simulation system with a control device and an emulator synchronized to receive input data at a common cycle, where the emulator adds time stamps to input data and performs boost calculations using snapshot data from the control device at a faster cycle, allowing for the reproduction of plant states and checking the impact of control logic changes before they occur.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the control device operates the plant in normal control mode, then the plant control function is maintained, but the control logic cannot be checked in advance for potential sudden changes in output values
Solution Approach 1:
The patent creates a copy of the control device called an emulator that replicates the control logic and calculation functions. This emulator runs in parallel with the actual control device, receiving the same input data and producing output values that can be compared. By copying the control system, the patent enables safety checking of control logic changes without affecting the actual plant operation, thus resolving the contradiction between maintaining control reliability and enabling control function testing.
Solution Approach 2:
The emulator performs calculations and generates output values in advance before the actual control device applies control logic changes. By using timestamp comparison, the emulator's earlier calculations allow operators to predict and verify the effects of control logic changes before they are implemented in the actual control device. This preliminary action enables safety verification while maintaining normal plant operation.
2Reliability
If the emulator performs calculations at the same cycle as the control device, then synchronization is maintained, but the ability to check control logic changes in advance is lost
Solution Approach 1:
The emulator is configured to perform calculations at a faster cycle than the control device, completing calculations before the control device's calculation time point. This time advance allows the emulator to generate predicted output values that can be compared with the control device's actual output values, providing a time buffer for checking control logic changes before they are applied to the actual plant.
Solution Approach 2:
The patent replaces the traditional synchronous calculation mechanism with an asynchronous mechanism using timestamp comparison. Instead of requiring the emulator and control device to calculate at exactly the same cycle, the system uses timestamp metadata to match and compare calculations that occurred at different times. This substitution enables the emulator to operate at a faster cycle while still maintaining accurate comparison capability.
3Productivity
If the control device calculates at a slower cycle, then processing load is reduced, but the ability to detect sudden changes in output values is diminished
Solution Approach 1:
The emulator creates a duplicate calculation system that operates independently from the control device. By copying the control logic and performing calculations in the emulator, the system can use faster calculation cycles without increasing the processing load on the actual control device. The emulator's faster calculations provide detailed output value changes that enhance detection precision, while the control device maintains its original slower cycle for actual plant control.
Data Source
AI summary
In this plant operation simulation system, a control device provides a time stamp to a snapshot of a calculation result by a control function of the control device at an arbitrarily defined time and transfers the snapshot to an emulator. By using the calculation result included in the snapshot transferred from the control device and input data to which a time stamp at or after a time indicated by the time stamp provided to the snapshot is provided, the emulator executes boost calculation for calculating a control model of the emulator at a cycle faster than the cycle of calculation by the control function of the control device until reaching a calculation time of the control function in the control device at a current time point.