The Siemens 6GT2821-1AC10 is an RF210R RFID reader from the SIMATIC RF200 family, designed to read and write ISO 15693 and ISO 18000-3 transponders at 13.56 MHz over an RS422 interface using the 3964R protocol. It integrates the antenna into a compact M18 x 71 mm threaded barrel with an M12 8-pin connector, rated IP67 for direct washdown and outdoor deployment on conveyor lines or access gates. The 20 mm read/write range depends on the transponder type — check the Siemens support note for your specific MDS Dxxx tag. Typical read and write access runs 0.6 ms per byte, with a maximum transfer rate of 26.5 kbit/s.
Runs on 24 V DC nominal (20.4 to 28.8 V range) and draws 0.05 A typical — light enough on the control transformer that you can share a 24 VDC supply with a small PLC without worrying about sag. The IP67 rating means the brass/nickel-plated housing and PBT face survive hose-down cleaning, so it fits food-and-bev or washdown stations where a standard IP20 sensor would fail. Shock resistance per EN 60721-3-7 Class 7 M2 at 500 m/s² and vibration at 200 m/s² — it holds up on a vibrating conveyor or a robot arm without losing the tag lock. The RS422 interface supports cable runs up to 1000 m, so the reader can sit at the far end of a long production line while the controller stays in the cabinet. The 3-color LED gives local status without needing a screen.
MTBF is listed at 505 a (years) — that's a calculated figure for continuous operation in a controlled environment, not a guaranteed service life, but it tells you the design reliability is solid for a fixed-installation reader.
Mounts via two M18 x 1 nuts included in the box — standard threaded barrel, so it drops into any 18 mm hole pattern. The M12 8-pin connector carries both power and RS422; no separate power cable needed. Silicon-free construction matters if you're placing it near coating or potting lines where silicone contamination is a concern. Not multitag-capable — reads one transponder at a time. For applications needing bulk reads of multiple tags in the field, you'd step up to a higher-end reader in the SIMATIC RF600 series.