The Siemens 6GT2821-4AC11 is a SIMATIC RF200 RF240R RFID reader with an integrated antenna, communicating via RS-232 using the 3964R protocol. It operates at 13.56 MHz and reads ISO 15693 and ISO 18000-3 transponders (MDS Dxxx types), with a maximum range of 65 mm — though that range depends on the specific transponder in use.
IP67 means the reader body is dust-tight and survives submersion in 1 m of water for 30 minutes — suitable for washdown zones on a production line, but not for continuous immersion or pressurized spray. The housing is PA6.6 in anthracite, fastened with two M5 screws, so it mounts directly to machine frames or brackets without a DIN rail. The 24 V DC supply (20.4 to 28.8 V range) draws 0.05 A typical — low enough to power from a standard 24 V sensor supply without worrying about the line drop over a 30 m RS-232 cable run. The RS-232 interface supports cable lengths up to 30 m, which is the practical limit for that protocol before signal degradation sets in. Read and write access times are both 0.6 ms per byte typical. For a 16-byte UID read that's under 10 ms, but if you're writing larger data blocks (say 128 bytes of user memory) expect roughly 77 ms per block — factor that into your cycle time budget. The reader is not multitag-capable, so it reads one transponder at a time. The 13.56 MHz HF band gives it better performance around metal and liquids than UHF, but the range is still limited to 65 mm max — this is a close-proximity station, not a conveyor portal reader.
Deployment context
This reader is designed for stationary read points on assembly lines, tool identification in machining centers, or access control at workstations where you need to identify a part or tool carrier within a 65 mm window. The RS-232 with 3964R protocol means it connects directly to a PC serial port or a serial-to-USB converter — no fieldbus gateway required, but you're limited to point-to-point topology. The 50 x 50 x 30 mm footprint and M5 mounting make it easy to retrofit into existing fixtures. The M12 8-pin connector carries both power and RS-232 signals, so keep the cable assembly short to maintain signal integrity — 30 m is the maximum, but for reliable communication in a noisy plant I'd keep it under 15 m and use shielded cable with the shield grounded at one end. The silicon-free construction matters if this goes into a paint shop or coating line where silicone contamination causes adhesion failures.