Safety Device OR-Link Wiring Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing safety devices for switching off electrical loads require additional inputs and control units for each safety switching device, leading to increased wiring effort and response time, and potential interference between devices.
Innovation Solution
Connecting safety devices via their safety-related outputs to form an OR link, allowing direct control of a common actuator with reduced wiring and faster response times, and incorporating a readback unit to prevent signal overwriting, along with a control line for coordinating signal outputs and error handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If safety devices are connected in series with separate inputs and control units, then each device can independently process safety signals, but the wiring effort and system complexity increase significantly
Solution Approach 1:
The patent merges multiple safety device outputs into a common output line where they are connected in parallel. This allows multiple safety devices to share a common actuator control line, reducing the number of separate wiring connections needed while maintaining independent safety monitoring capabilities through the OR-link logic.
Solution Approach 2:
The common output line serves multiple safety devices simultaneously, allowing a single actuator control line to receive and process safety signals from multiple sources. This universal connection approach reduces overall system complexity while maintaining the ability to independently monitor each safety device's status.
2Reliability
If multiple safety devices control separate actuators, then each device can independently trigger shutdown, but the response time increases due to signal propagation delays
Solution Approach 1:
By merging multiple safety device outputs onto a common output line that directly controls a single actuator, the patent eliminates intermediate signal propagation steps. The OR-link configuration ensures that any safety signal from any device immediately affects the actuator state, reducing overall response time while maintaining reliable shutdown capability.
3Device complexity
If safety devices share a common output line, then wiring effort is reduced, but signal interference and overwriting may occur between devices
Solution Approach 1:
The patent implements preliminary anti-action by using an OR-link configuration where safety signals are logically combined before reaching the actuator. This logical OR operation prevents signal overwriting by ensuring that any active safety signal (regardless of which device generated it) maintains its effect on the actuator, thereby preserving signal integrity while allowing shared output wiring.
Solution Approach 2:
The system incorporates feedback mechanisms where each safety device monitors the common output line to detect the presence of other safety signals. This feedback allows devices to coordinate their output behavior, preventing conflicting signals from causing interference while maintaining the benefits of the shared output configuration.
Data Source
Figure 1
Figure 2
AI summary
The device (1) has a controlling and evaluation unit (2) designed for outputting switching signals to a safety-adjusted output (OSSD-LG1), where the output is provided for switching an actuator. The controlling and evaluation unit comprises a back-read unit (OSSD-MON1) to backread the switching signals at the output. The controlling and evaluation unit is designed to read and/or output control information at a control line (TOKEN). A switching unit (CTRL1) is designed for switching an object detection signal.