IEEE 2839-2021 pdf download

IEEE 2839-2021 pdf download.IEEE Recommended Practce for Vital Computer for Rail Safety-Related Applicaton
4. Environmental conditions Vital computer should meet the following environment conditions:
a) Altitude: 2500 m
b) Operating temperature: −40 °C to +85 °C
NOTE 1—Three levels of altitude are defned with a maximum value of 1400 m in IEC 62498-3 8 , and the altitude should be specifed by the customer for more than 1400 m. Considering the possibility of higher altitude (more than 1400 m) for a vital computer (VC) located around the world, this recommended practice defnes the maximum allowable value as 2500 m which covers most applications of a VC, and it is feasible in technical realization. The extreme values (such as 5100 m in China rail applications) are not considered.
NOTE 2—The range of operating temperature (including storage temperature) is not classifed on the basis of climate conditions of different regions in the world.
The temperature range −40 °C to +85 °C covers most climate conditions and this temperature range is consistent with the limits for industry-level electronic elements.
NOTE 3—Operating temperature means the temperature of air around vital computer modules (plug-in units), but not the ambient temperature of the application system. In general, the modules of vital computers are installed inside the equipment of the application system, temperature inside the equipment is higher than ambient temperature of application system for the reason of heating, therefore necessary methods of temperature control (such as ventilation and air conditioning) should be adopted by application systems.
NOTE 4—For some special modules (such as power supply), higher temperatures may result in the reduction of performance (such as decreasing of output power). In this case, clear information should be informed to the application system by the vital computers. c) Storage temperature: −40 °C to +85 °C d) Relative humidity: Average value in a year is less than 75%, average value in a month is less than 95% e) Vibration and shock: Comply with IEC 61373 f) Pollution protection: Medium level of environmental pollution defned in IEC 62498-3 g) Electromagnetic compatibility (EMC): Comply with IEC 62236-4
NOTE 5—As the basic modules of vital computers exist in the form of plug-in units, part of EMC performance (i.e., static charge immunity) rely on the EMC design of the application system. So that application system should take suffcient consideration for the EMC during the design of the rack or the cabinet which contain the basic modules of the vital computers, where available methods are shielding and/or earthing.
5. General requirements
A vital computer (VC) used for a rail safety-related application is a control system based on computer technology, communication, and functional safety as well as security. A VC is composed with basic functional modules such as main process, input, output, and communication.
A VC is capable of supporting an application system to combine basic modules and application software for specific safety-related application functions. An application system includes but is not limited to:
a) Equipment in signaling system such as automatic train protection (ATP), computer-based interlock (CI), radio block center (RBC), train control center (TCC), and zone controller (ZC)
b) Control system for platform edge doors and train doors
c) Power supply system for train traction
d) Onboard control system applied for braking, traction, and network
NOTE—The types of basic modules of VCs depend on the functions and performance of an application system. As complexity and differentiation exist in rail safety-related application systems and taking consideration of requirement changes due to technology development in the future, the types of basic modules might not cover all applications.
This recommended practice defnes only the basic modules. Specifc function modules should only be considered by application systems. 9 Safety is a critical performance of a VC. Designing, manufacturing, and integrating (except application development, implementation, and operation) of a VC should be performed in accordance with IEC 62278 (all parts), IEC 62279, and IEC 62425.IEEE 2839 pdf download.IEEE 2839-2021 pdf download