Siemens 505-6504 W 4-Slot Chassis

Siemens 505-6504 W is a four-slot mounting chassis for the SIMATIC 505 programmable logic controller (PLC) family, providing a compact backplane that hosts up to four expansion or I/O modules in a single enclosure. This base is part of the SIMATIC 505 ecosystem and is designed to support modular configurations and straightforward wiring in industrial control panels. It sits alongside larger backplanes in the 505 lineup, with 8-slot (505-6508), 11-slot (505-6511, with redundant configurations), and 16-slot (505-6516) variants, enabling scalable deployments from four to sixteen slots. In typical installations the 505-6504 base serves as the core housing for a processor or controller module together with I/O expansion modules to form a compact control rack. The 505-6504 is well-documented in legacy Siemens TI-505 materials and distributor listings as the four-slot chassis for this system, making it a common choice for retrofits or rebuilds of older automation projects.