Ladder Program Infinite Loop Escape Unit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ladder programs often get stuck in infinite loops, making it difficult to detect and escape such loops during execution, which can disrupt normal machine control.
Innovation Solution
A controller with an infinite loop escape unit that forcefully sets the execution condition for a jump instruction to false, using an infinite loop occurrence condition information table to record and reference the state of execution condition signals, allowing the loop to be escaped by overwriting the signal state of a closed contact within the jump instruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a jump instruction is used to repeatedly execute a specific process in a ladder program, then the process can be looped until an execution condition becomes false, but the program may get stuck in an infinite loop if the execution condition never becomes false
Solution Approach 1:
The system performs preliminary detection of infinite loops by monitoring execution conditions before the loop completes its natural termination. The detection unit identifies when an execution condition signal remains continuously true for an abnormal duration, allowing the system to intervene before the infinite loop causes serious disruption to machine control operations
Solution Approach 2:
An intermediary escape mechanism is introduced between the jump instruction and the loop execution flow. When an infinite loop is detected, the escape unit acts as a mediator to forcibly terminate the loop by setting the execution condition signal to false, providing a controlled exit path that prevents the harmful infinite loop while maintaining the beneficial loop structure
2Difficulty of detecting and measuring
If the execution condition signal is monitored to detect infinite loops, then the location of the infinite loop can be identified, but the program cannot escape the loop without additional escape mechanisms
Solution Approach 1:
A feedback mechanism is implemented where the detection unit continuously monitors execution condition signals and provides information about loop status to the escape unit. When the detection unit identifies an infinite loop condition (execution condition signal remaining continuously true), it triggers the escape unit to respond by forcibly setting the execution condition to false, creating a closed-loop control system that automatically detects and resolves infinite loops
Solution Approach 2:
The system performs self-service by automatically detecting and escaping from infinite loops without requiring external intervention. The detection unit monitors the execution condition signals, identifies infinite loop conditions, and the escape unit autonomously terminates the loop by overwriting the execution condition signal, allowing the system to self-correct programming errors
Data Source
AI summary
A controller and an editor that enable a ladder program to escape an infinite loop are provided.A controller that can detect a loop process being stuck in an infinite loop during execution of a ladder program includes an infinite loop escape unit for escaping the infinite loop by forcefully making an execution condition for a jump instruction false when the infinite loop occurs, the jump instruction being included in the loop process.