The S5-115H is a fault tolerant programmable controller for the lower and mid performance ranges. It is at home wherever process downtimes must be avoided. The S5-115H is always put into service when the probability of a controller failure must be reduced to an ablolute minimum expensive raw materials cannot withstand process interruptions production downtimes cost a great deal of money. Whether in sophisticated chemical processes, in manufacturing or in power supply systems, the high-availability S5-115H can be assembled economically and with little configuring overhead from standard SIMATC S5 components. Servicing, corrective maintenance and repairs can be done during operation because the system is able to tolerate the failure of any redundant module. The S5-115H allows you to utilize the full advantages of the S5-115U-range programmable con- trollers in high-availability systems. You simply write your process-related control program in the usual way and then enter the configuring data with the COM 115H system software.
SIEMENS (1990) SIMATIC S5-115H Programmable Controller Manual