Power Supply Shutdown Timing for Reliable Pre-Stop Processing
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Solution Overview
Problem
Conventional control systems face challenges in determining the appropriate timing for stopping power supply and ensuring sufficient execution time for pre-stop processing, especially in environments with fluctuating input voltages, leading to high frequencies of incorrect system shutdowns and inadequate operation termination.
Innovation Solution
A control system with a power supply unit that includes a power converting unit, a first detection unit for comparing input voltage with a threshold voltage, and a calculation unit that executes pre-stop processing based on adjustable measurement times, allowing external adjustment of threshold voltages and measurement times to optimize power supply determination and processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the threshold voltage is set to be higher than a general value, then the determination of power supply stoppage becomes more sensitive, but the frequency of system shutdowns increases and operation rate decreases
Solution Approach 1:
The system introduces a predetermined time period measurement mechanism that activates when voltage drops below the threshold. Instead of immediately shutting down the system upon threshold violation, the system waits for a predetermined time to confirm sustained power supply stoppage. This preliminary action filters out transient voltage fluctuations and prevents false shutdowns, maintaining system operation during temporary voltage dips while still detecting genuine power failures.
2Productivity
If the threshold voltage is set to be lower than a general value, then the frequency of system shutdowns decreases, but the voltage charged into the capacitor becomes lower and execution time of pre-stop processing becomes insufficient
Solution Approach 1:
The system performs pre-stop processing (such as saving data to non-volatile memory) during the predetermined time period before actual system shutdown. By initiating these critical operations in advance when voltage first drops below the threshold, the system ensures that essential data preservation and cleanup tasks are completed even with limited capacitor voltage, guaranteeing reliability of pre-stop processing while maintaining higher system operation rates.
3Device complexity
If a fixed threshold voltage is used, then the control system is simple to implement, but it cannot adapt to frequent voltage changes in production environments
Solution Approach 1:
The system employs a dynamic threshold voltage mechanism that can be adjusted based on operating conditions. The threshold voltage is no longer fixed but can be modified to adapt to different production environments and voltage fluctuation patterns. This dynamic adjustment capability allows the system to optimize its sensitivity and response characteristics for various operational scenarios while maintaining reasonable implementation complexity through structured control logic.
Data Source
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AI summary
This power supply unit of a control system outputs a notification signal to a calculation unit when a time in which an input voltage becomes smaller than a threshold voltage exceeds a prescribed first measurement time. When detecting that a predetermined second measurement time has elapsed after the notification signal has been received, the calculation unit outputs an instruction signal instructing the execution of a process before a stop in preparation for a prescribed stop of power supply, and executes the process before the stop in place of the current process. Settings of the threshold voltage and the second measurement time are configured to be changeable by means of an external operation.