Railway-rated CPU with deterministic scan budget
The Siemens 6AG1317-2EK14-2AY0 is a S7-300 CPU 317-2 PN/DP variant hardened for railway rolling stock, carrying EN 50155 certification (Sections 4, 5 and 12; T1, Category 1, Class A/B per EN 50155:2007). Rated operating range is -25 °C to +55 °C (T1) with a maximum short-term peak of +60 °C — the wider thermal envelope over the standard 317-2 PN/DP (0 to 60 °C) is the main reason to spec this order code over the base 6ES7317-2EK14-0AB0. It supports 8 FM function blocks, along with LAD, FBD, STL, SCL, GRAPH, HiGraph, and CFC programming languages, plus IRT for isochronous real-time PROFINET communication.
What does the EN 50155 rating mean for your line?
EN 50155 T1 means the CPU is qualified for continuous operation at +55 °C ambient inside a sealed enclosure, with no derating required up to that ceiling. The -25 °C minimum covers cold-start in unheated wayside cabinets. The 40 mm width (one S7-300 slot) and 125 mm height fit standard DIN-rail enclosures alongside power supplies and I/O slices. Depth is 130 mm — verify clearance against the enclosure door or gland plate. Integrated PROFINET interface supports IRT (Isochronous Real-Time) for deterministic motion or high-speed I/O buses where jitter below 1 ms is non-negotiable. UDP and TCP/IP are available via the same port with loadable function blocks.