Roll Door Control with Dual Speed and Direction Verification
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Solution Overview
Problem
Existing roll door control systems lack the necessary safety measures to ensure secure and foolproof opening and closing, particularly in environments where people or objects may be in close proximity, and there is a demand for higher security standards.
Innovation Solution
A control unit system that includes an inverter, drive unit, encoder, and detection unit, which communicates through dedicated cables to monitor and control the speed and direction of the roll door, stopping the movement if any discrepancies are detected, and includes a detection unit to prevent objects from getting stuck during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional roll door control systems are used, then the device complexity is low, but the safety and security class is insufficient
Solution Approach 1:
The control system is segmented into multiple independent monitoring channels: inverter feedback channel (monitoring speed and direction from inverter) and encoder feedback channel (monitoring speed and direction from encoder). Each channel independently verifies the drive unit's operation, and either channel can trigger an emergency stop, distributing the safety function across separate components rather than relying on a single complex system
Solution Approach 2:
The system implements dual feedback mechanisms: the inverter provides feedback on actual speed and direction to the control unit, and the encoder independently provides position-based speed and direction feedback. The control unit continuously compares these feedback signals with commanded values, creating a closed-loop verification system that enhances safety through redundant feedback paths
2Reliability
If speed and direction monitoring is implemented, then the safety class improves, but the loss of time due to verification processes increases
Solution Approach 1:
The monitoring of speed and direction is performed continuously throughout the entire door operation without interruption. The control unit constantly receives and compares feedback signals from both the inverter and encoder, ensuring uninterrupted verification that prevents safety gaps while maintaining continuous operational awareness
Solution Approach 2:
The system performs preliminary verification by comparing feedback signals with commanded values before discrepancies can lead to unsafe conditions. The continuous monitoring detects deviations in real-time, allowing the control unit to trigger emergency stop before an unsafe state fully develops, preventing rather than merely responding to hazards
3Measurement precision
If dual monitoring channels (inverter and encoder) are used, then the measurement precision of speed and direction improves, but the device complexity increases
Solution Approach 1:
The control unit receives feedback signals from both the inverter (providing direct speed and direction measurements) and the encoder (providing position-based speed and direction calculations). By processing and comparing these two independent feedback sources, the system achieves cross-verification that enhances measurement precision and reliability
Solution Approach 2:
The monitoring function is divided into two separate measurement paths: one through the inverter that directly measures motor speed and direction, and another through the encoder that calculates speed and direction from position changes. This segmentation allows each component to perform its specialized measurement function independently, improving overall precision through diversity of measurement methods
Data Source
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AI summary
Disclosed is a method and a control unit (10) of a roll door control system for controlling opening and closing of a roll door (1). The roll door control system comprises an inverter (20) connected to the control unit (10), a drive unit (30) for driving the roll door (1) for opening and closing, connected to the inverter (20) and an encoder (40) connected to the control unit (10) for monitoring a position of the roll door (1). The control unit (10) obtains from the inverter (20) information on first speed and first direction of the drive unit (30), and from the encoder (40) information on position of the roll door (1), which it uses to determine second speed and second direction of the drive unit. The control unit further stops the drive unit (30) in case any of first speed, second speed, first direction, second direction do not match an instruction sent to the inverter (20).