1 IEC 61508: Functional safety of electrical/electronic/programmable electronic safety related systems

(1) The IEC61508 standard specifies the basic safety requirements for both conventional system operation and fault prediction capability. These requirements cover general safety management systems, specific product designs, and process designs that comply with safety requirements, with the goal of avoiding both systematic design failures and random hardware failures.

(2) The main objectives of the IEC61508 standard are:

Provide a systematic method for safety supervision of all components of safety related systems, including software and hardware, within their lifecycle; Provide methods for determining security related system security function requirements; Establish basic standards that can be directly applied to all industrial fields. At the same time, it can also guide standards in other fields, making the drafting of these standards consistent (such as basic concepts, technical terminology, requirements for prescribed safety functions, etc.); Encourage operators and maintenance departments to use computer-based technology; Establish a standardized architecture and system with unified and coordinated concepts.

2 IEC61511: Functional safety requirements for safety instrumented systems in the process industry field

(1) IEC61511 is a functional safety standard specifically designed for safety instrumented systems in the process industry. It is a professional field standard launched by the International Electrotechnical Commission after the functional safety basic standard IEC61508. The coordinated standard for IEC61511 in China is GB/T 21109. In the process industry, instrument safety systems are used to perform instrument safety functions, and the IEC61511 standard addresses the issue of what level of safety integrity and performance instruments should achieve.

(2) For the confirmation of safety related device safety functions, SIL level is a widely recognized method for defining safety integrity worldwide. For the process control industry, the relevant international standards mainly include IEC 61508 standard (the basis for designing and operating safety instrumented systems), IEC 61511 standard mainly focuses on systems for process control applications, and device designers follow IEC 61511 standard and complete the design according to IEC 61508 standard.

3 ISO13849-1: Mechanical safety The relevant safety parts of the control system Part 1: General Principles for Design

(1) The new version of ISO13849-1 standard will officially come into effect at the end of 2011, which will be a new milestone in the field of mechanical functional safety. In the past, the requirement for system certainty has been increased by adding assessments on the probability of system failures, allowing for comprehensive safety assessments from components to the system. At the same time, this standard also provides designers with more quantifiable design implementation methods, such as adding system safety level (PLr), system mean time to failure (MTTFd), system diagnostic detection range (DC), common cause failure prevention (CCF) and other parameters, effectively solving the problem of the original EN954-1 standard being unable to quantitatively judge system safety.

(2) The new version of ISO13849-1 standard provides more effective security assessment solutions for some new control methods. It can enhance the safety level of increasingly complex mechanical equipment, ensure production safety and efficiency, and combine new technologies and design experience to help enterprises improve overall efficiency, productivity, and flexibility, ensure continuous production, reduce unexpected downtime, and lower development, operation, and maintenance costs. Implementing this standard as soon as possible can ensure that mechanical manufacturers can seize the market advantage in fierce competition.

4 IEC62061: Mechanical safety Functional safety of electrical, electronic, and programmable electronic control systems related to safety

(1) The IEC/EN 62061 and EN ISO 13849-1:2008 standards both include electrical control systems related to safety. By adopting these two standards, the same level of security performance and security integrity can be achieved. The methods used in each standard may vary, but they are all suitable for their respective readers. EN ISO 13849-1: In Table 1 of its explanatory section, 2008 provides a limited situation. When using complex programmable techniques, the highest PL performance level should be defined as PLd.

(2) In order to adopt complex security functions that can be executed by previously non-traditional system structures, the IEC/EN 62061 standard provides corresponding methods. In order to provide a more direct and simpler path for executing more traditional security functions using traditional system architectures, EN ISO 13849-1: The 2008 standard also provides corresponding methods. The important difference between these two standards is that they are applicable to different technical fields. The IEC/EN 62061 standard is limited to the field of electrical systems. EN ISO 13849-1: The 2008 standard applies to start-up, hydraulic, mechanical, and electrical systems. The main defined parameters are PFH, MTTF, DC, SFF, etc.

5 IEC61326-3-2: Electrical equipment for measurement, control, and laboratory use Requirements for Electromagnetic Compatibility (EMC): Safety related systems and systems used for performing safety related functions (functional safety)

(1) The IEC 61326-3-1 and IEC 61326-3-2 standards have been released, which specify additional requirements for the immunity level of safety related equipment, including extreme situations with very low probability of occurring in any location. Severe electromagnetic phenomena, such as instantaneous pulses, occur during the operation of experimental simulation equipment, simulating the transient state of analog digital circuits or digital signal transmission. In order to increase the confidence level of the electromagnetic immunity of the Safety Integrity Level (SIL), more pulses or longer test times should be applied and the test level should be improved compared to the basic standard when conducting anti electromagnetic performance tests. For example, for equipment used for SIL3, the level of electrical fast transient test is 4kV, and the test duration should be 5 times the time specified in the basic standard.

6 ISO26262: Functional safety in the design of road vehicle systems

(1) The purpose of developing the ISO 26262 standard is to provide people with a better understanding of safety related functions and to explain them as clearly as possible. ISO 26262 is derived from the basic standard IEC61508 for functional safety of electronic, electrical, and programmable devices. It is mainly positioned in the automotive industry for specific electrical components, electronic equipment, programmable electronic devices, and other components specifically used in the automotive field, aiming to improve the international standards for functional safety of automotive electronic and electrical products. Once this standard was proposed, it received high attention from major automobile manufacturers and auto parts suppliers, and actively promoted its implementation in product development.

(2) Based on the IEC 61508 standard, the ISO 26262 standard defines the safety of use for electrical and electronic systems. A major challenge in automotive design is how to assess potential hazards and risks in advance and take appropriate measures to reduce these risks. In order to facilitate this process, ISO stipulates that a "hazard and risk analysis" must be conducted at the beginning of development work.

(3) The automotive industry uses high-performance electronic devices for vehicle safety control. The ISO 26262 functional safety standard, jointly developed and recognized by globally renowned automotive manufacturers, specifies the requirements for the design of electronic components, software and hardware products used in vehicles. With the promulgation and implementation of ISO 26262, the potential risks of vehicles and the degree of harm in the event of accidents can also be reduced in the future, thereby enhancing the adaptability and competitiveness of the domestic vehicle industry in the international future.

7 IEC61800-5-2: Standard for adjustable speed electric equipment Part 5-2: Functional Safety Requirements

(1) IEC61800-5-2 defines the safety function of integrated safety drives, which includes a series of stop functions, namely: STO (Safe Torque Off) for safe disconnection torque/safe interruption torque; Safety Stop 1/SS1/Safety Stop 2/SS2; Safety Operation Halt

(2) IEC61800-5-2 also defines some monitoring functions, including acceleration safety limits; Step safety restrictions; Safety restrictions on movement direction; Speed safety limit; Torque/force safety limit; Location security restrictions; Temperature safety limits for electric motors.

(3) The IEC61800-5-2 standard mainly proposes functional safety requirements for safety encoders, safety decoders, AC servo systems, servo drives, servo motors, and other systems. For example, motor controllers that meet functional safety technical requirements will support safety functions such as Safe Torque Stop (STO) and Safe Stop 1 (SS1) to prevent accidental starting. Product design must comply with the requirements of EN 61800-5-2 standard. The IEC61800-5-2 standard has been converted into a national standard, with the standard number GB/T 12668.5.2. The corresponding domestic standardization committee is the National Technical Committee for Standardization of Power Electronics, Speed Control Electrical Transmission System Semiconductor Power Converter Technical Committee (TC60/SC1).

8. EN50156 IEC 61784-3: Measurement and control of digital data communication - Part 3: Industrial network functional safety code

This standard mainly defines the following content:

(1) Implement the basic principles of IEC 61508 requirements for safety related data communication, including provisions for potential erroneous transmission, response measures, and impact on data integrity

(2) Common content implemented by various technologies

(3) Independent description of functional safety regulations for various communication protocol clusters

(4) Several secure communication layers have been specified as part of the communication service specification in the IEC61784-1 and IEC61158 system standards

9. EN50126 Railway Applications: Reliability, Availability, Maintainability, and Safety (RAMS) Specifications and Instructions

This standard defines the RAMS (reliability, availability, maintainability, and safety) of a system, which includes reliability, availability, maintainability, and safety. It also specifies the management and requirements for RAMS at various stages of the safety lifecycle. RAMS, as an important characteristic of system service quality measurement, is obtained through design concepts and technical methods at various stages of the entire system safety lifecycle.

10. EN50128 Railway Applications: Software for Railway Control and Protection Systems

The software of railway control and protection systems has been classified into Safety Integrity Levels (SIL), and corresponding standards have been formulated for different safety requirements. In the overall software development, evaluation, and testing process, including software requirement specifications, testing specifications, software structure, software design and development, software inspection and testing, software and hardware integration, software confirmation and evaluation, quality assurance, lifecycle, documentation, etc., corresponding specifications and requirements have been proposed according to different levels.

11. EN50129 Railway Applications: Safety Related Electronic Systems

For safety management, the concept of safety lifecycle proposed in IEC61508 is introduced, which means that the safety part of safety related systems should be designed according to this step during the design process, and a full process safety assessment and verification should be carried out to further reduce human errors related to safety and thereby reduce the risk of system failure.

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