Encoder Safety Module for Retrofitting Safe Drive Control
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Solution Overview
Problem
Existing drive systems in automation systems lack comprehensive safety solutions that are both cost-effective and capable of meeting stringent safety requirements, particularly when not originally designed with safety encoders or interfaces, and retrofitting such systems is technically complex and costly.
Innovation Solution
A safety module is integrated into the drive system, comprising a protocol active unit, a protocol passive unit, and a safety logic, which communicates with the encoder and drive units to check encoder data against safety criteria, allowing for safe operation without modifying existing encoder protocols or interfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If safety encoder interfaces (Hiperface DSL Safety, EnDat 2.2 Safety) are used to ensure comprehensive safety operation, then safety compliance and reliability are improved, but device complexity and cost increase significantly
Solution Approach 1:
The safety module is segmented into distinct functional units: a protocol active unit for encoder protocol communication, a protocol passive unit for drive protocol communication, and a safety logic unit for safety assessment. This segmentation allows each unit to be optimized independently while maintaining overall safety compliance without requiring comprehensive safety encoder interfaces throughout the entire system.
Solution Approach 2:
The safety module acts as an intermediary component between the encoder unit and drive unit. It receives encoder data via the protocol active unit, processes safety assessment through the safety logic, and communicates with the drive unit via the protocol passive unit. This intermediary approach enables safety monitoring without requiring the encoder or drive units themselves to be safety-certified, thereby reducing overall system complexity.
2Reliability
If safety encoder interfaces are implemented for comprehensive safety operation, then safety compliance is improved, but cost increases
Solution Approach 1:
The safety module uses standard, non-safety-certified encoder units and drive units instead of expensive safety-certified components. By implementing safety assessment logic in the intermediary safety module rather than requiring safety-certified encoders, the system achieves safety compliance using cheaper, more readily available components that do not carry the premium cost of safety certification.
3Reliability
If drive systems are retrofitted with safety concepts not originally intended, then safety compliance is improved, but technical complexity and cost increase
Solution Approach 1:
The safety module is designed with universal functionality to work with standard encoder protocols (such as EnDat, BiSS, SSI) and drive protocols without requiring safety-specific modifications to the existing encoder or drive units. The protocol active and passive units handle protocol conversion and communication, enabling the safety module to be retrofitted into existing drive systems regardless of their original safety design, thereby simplifying the retrofit process.
Data Source
AI summary
A safety module for a secured drive control of an automated drive system is configured to receive encoder data sent from an encoder unit to a drive unit, based on an encoder protocol via a protocol active unit. The safety module is configured to forward the encoder data from the protocol active unit to a safety logic and a protocol passive unit, check the forwarded encoder data with the aid of the safety logic for correspondence with predetermined safety criteria relating to operation of a motor unit, and transmit the forwarded encoder data via the protocol passive unit to the drive unit, in respective data packets based on the encoder protocol. The safety module can stop operation of the motor unit with the aid of the safety logic, if the encoder data does not correspond to the predetermined safety criteria. A corresponding drive system and automation system are also provided.