Gate Detection Grid Frequency Signaling for Reliable Blanking Control
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Solution Overview
Problem
Existing door safety systems with detection grids are prone to errors due to incorrect activation of blanking mode by objects other than the door leaf, leading to potential collisions, and complex communication protocols require additional hardware and setup.
Innovation Solution
A method using pulsed signals at different frequencies to differentiate between normal operation, error states, and blanking mode, allowing the door control to distinguish between these states without additional signal paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If detection devices are positioned as close as possible along the travel path for reliable detection, then detection reliability is improved, but the door itself may trigger the detection devices during closing or opening movement
Solution Approach 1:
The detection grid transmits a pulsed signal to the door control at a first frequency in a nominal operating state. The pulsed signal with its specific frequency serves as a recognizable identifier that distinguishes normal detection operations from actual fault conditions, allowing the door control to ignore temporary activations during door movement while still responding to genuine obstacles.
Solution Approach 2:
The system changes the signal parameter (frequency) to differentiate between operational states. By transmitting the pulsed signal at a specific first frequency during normal operation and switching to a non-pulsed second signal (or different frequency pattern) when actual faults occur, the system enables reliable distinction between door-induced activations and real collision hazards.
2Productivity
If a blanking function is implemented to prevent error signals during closing movement, then operational continuity is improved, but objects other than the door leaf can incorrectly activate blanking mode causing collisions
Solution Approach 1:
The detection grid continuously provides feedback to the door control about its operational state through the pulsed signal. The door control uses this feedback to understand when the door is actively closing (nominal operating state) and can appropriately respond to detection device activations, distinguishing between expected door-induced signals and actual obstacles that require stopping.
Solution Approach 2:
The system dynamically adjusts its response based on the current operational state. When the door is in the process of closing and the detection grid receives the pulsed signal at the first frequency, the system is configured to ignore detection activations during this period. However, when the door is stationary or in other states, the system remains vigilant and can trigger safety responses to actual obstacles.
3Measurement precision
If complex communication protocols are used to improve detection accuracy, then detection precision is improved, but additional hardware and setup requirements increase
Solution Approach 1:
The existing signal path between the detection grid and door control is made multi-functional by having it carry both the operational status information (through the pulsed signal frequency) and the detection state information. This eliminates the need for separate communication protocols or additional hardware, achieving enhanced detection precision while maintaining system simplicity.
Data Source
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AI summary
Method for operating a door (4) with a door leaf (5) movable between a closed position and an open position along a travel path, with a door drive (7) coupled to the door leaf (5), with a door control (8) controlling the door drive (7), and with at least one detection grid (10) having a plurality of detection devices (11) arranged at a distance along the travel path and connected to the door control (8) via a signal path (9), wherein the detection devices (11) assume an activated state upon detecting an object in a detection area assigned to them, wherein the detection grid (10) transmits a pulsed first signal to the door control (8) via the signal path (9) in a nominal operating state (A), when none of the detection devices (11) is activated,wherein the detection grid (10) transmits a non-pulsed second signal to the gate control (8) via the signal path (9) in a fault state (B), characterized in that the detection grid (10) transmits the pulsed first signal at a constant first frequency (f1) in the nominal operating state (A) and that the detection grid (10) transmits a pulsed third signal with a second frequency (f2) deviating from the first frequency (f1) via the signal path (9) to the gate control (8) in a third operating state (C) deviating from the nominal operating state (A) and the fault state (B).