The Siemens 6ES7417-4HL00-0AB0 is a SIMATIC S7-400H CPU 417H central unit designed for redundant S7-400H systems. It carries 4 MB of memory, split evenly into 2 MB for code and 2 MB for data, and provides four interfaces: one MPI/DP, one DP, and two dedicated ports for sync modules that keep the paired CPUs in lockstep for fault-tolerant operation.
Integration into a redundant rack
The CPU 417H mounts into a standard S7-400 rack (UR2-H or similar) and connects to its redundant partner via the two sync-interface ports using fiber-optic sync modules. The MPI/DP port handles programming and HMI communication; the separate DP port can run a PROFIBUS DP line for distributed I/O. Memory of 4 MB is adequate for medium-to-large process or factory automation applications — think batch control, conveyor coordination, or safety-instrumented system logic running on the redundant pair.