Russian AUTOMATED TRAFFIC CONTROL SYSTEMS home Services Projects Solutions Certificates Partners Vacancies Contacts Automated process control systems (APCS) Systems of increased reliability Siemens H-systems The redundant Siemens S7-400H system develops the concepts of building control systems with increased reliability, the foundations of which were implemented in the controllers of the SIMATIC S5 family. The reliability of the system is supported by the operating system and the hardware of the CPU 414-4H or CPU 417-4H. The basic principle of the Siemens S7-400H programmable controller is the principle of hot backup with support for bumpless automatic switching to the backup base unit in case of failure of the master base unit. According to this principle, in the absence of faults, both base units are active and synchronously execute the same program. Both blocks synchronously form control actions, but these actions are output through the output modules only from the master block. In the event of a failure, all control functions are taken over by a functional controller unit. Reliable high-speed communication is required for guaranteed bumpless switching of the reserve between the base units of the controller. This link is maintained over fiber optic cables connecting the two CPUs. Synchronization functions on these cables are performed automatically by the controller operating system and do not require user programming. The use of the S7-400H controller provides a number of advantages: - Прозрачное программирование.Программы могут быть написаны на всех доступных для S7-400 языках. Программа, написанная для обычного центрального процессора, может выполняться и центральным процессором резервированного контроллера и наоборот. При написании программы учитываются только технологические особенности объекта управления. Вопросы повышения надежности функционирования системы решаются операционной системой и аппаратной частью контроллера. Дополнительное программное обеспечение необходимо только для конфигурирования резервированной системы. - Стандартная обработка данных. С точки зрения пользователя в контроллере S7-400Н есть только один центральный процессор и одна программа. - Быстрое безударное переключениеfrom master to slave with a typical switching time of 30 ms. During the switchover period, the operating system eliminates the possibility of data loss or interrupt signals. - Automatic synchronization of central processors after replacing one of them. After replacing one of the central processors, it is envisaged to perform automatic bumpless synchronization with the transfer of all current data (programs, data blocks, dynamic data, etc.) to the memory of the processor included in the operation.