Product Overview

The 6ES5450-8MD11​ is a SIMATIC S5-450 series digital output module from Siemens, engineered for the compact S5 rack line — S5-90U, S5-95U, S5-100U central racks and their distributed counterparts ET 100U and ET 200U. Where the far more common 6ES5441-4UA12 compact DO gives you 32 channels of 24 V DC / 0.5 A (perfect for solenoids, pilot valves, beacon stacks), the 6ES5450-8MD11​ goes to the opposite corner: only 4 outputs, but each switches 115/230 V AC at 1 A​ with galvanic isolation and a 10 A fast-blow fuse per channel. This makes it the compact rack’s native way to drive mains-voltage loads — contactor coils, motor-starter coils, heater-band SSR triggers, 230 V tower strobes, local HMI power relays — without stacking interposing relays between a 24 V DC DO and the AC load.Each of the 4 outputs on the 6ES5450-8MD11​ is a semiconductor (triac/AC-static) switch rated 47–63 Hz, with a “0” residual current max 3–5 mA (typical of AC static outputs — the leak current that keeps a neon or a poorly-suppressed contactor coil faintly alive, hence the reminder to use RC snubber or proper coil suppression on inductive AC loads). The module is floating/isolated​ — each output channel’s AC load side is galvanically separated from the compact rack’s internal 5 V/24 V backplane and from the other channels’ AC domains, meaning you can land, say, 115 V on Output 0 (feed from a control-transformer secondary) and 230 V on Output 1 (feed from mains via isolator) on the same 6ES5450-8MD11​ without backfeed — something the non-isolated 5441 cannot do. A red LED per channel flags fuse-blown (the 10 A fast-blow is user-replaceable at the module front, not buried behind the rack), and the module dissipates ~3.5 W total — modest, because only 4 channels and AC static switches run cool. Mechanical footprint is compact shallow profile like the 5441/5420 siblings: ~210 × 263 × 35 mm class, ~0.315 kg, IP20 control-cabinet.Siemens placed the 6ES5450-8MD11​ into PM500 effective 1 Oct 2020, “deleted without replacement” — no S5-successor (the S7-1500 / ET 200SP migration would be the macro replacement, but no like-for-like compact AC DO exists in current Siemens catalogue). Hence the 6ES5450-8MD11​ today lives in legacy-MRO: refurb/NOS/broker feeding storerooms that still run S5-90U/95U/100U compact racks where a 230 V contactor coil or a heater SSR trigger is cheaper to land on a 6ES5450-8MD11​ than to re-panel the machine with an interposing-relay bank fed from a 5441. For MRO teams, the 4-channel density feels odd at first (why only 4?), but the answer is thermal & isolation: switching 230 V AC @ 1 A static, with per-channel fuse and per-channel isolation, won’t fit 32 channels in the compact envelope — physics + VDE clearance forces the low channel count.

Technical Specifications