What it is and what it does
The Siemens 6GT2821-4AC32 is a SIMATIC RF240R RFID reader from the RF200 family, designed for reading and writing to ISO 15693 transponders (MDS Dxxx) via a 13.56 MHz radio interface. It connects to an IO-Link master V1.0 over a standard M12 4-pin connector, with a maximum cable run of 20 m between master and device. The integrated antenna gives a read/write range up to 65 mm, though actual range depends on the transponder type used. The housing is IP67-rated, anthracite PA6.6, measuring 50 x 50 x 30 mm, and mounts via two M5 screws. It draws 0.05 A typical at 24 VDC (20.4 to 28.8 V range). A 3-color LED provides local status indication. The unit is silicon-free and not multitag-capable — it handles one tag at a time. Read and write access times are 40 ms per byte typical. The radio transfer rate is 26.5 kbit/s maximum, and the IO-Link communication runs at 38.4 kbit/s. Operating temperature range is -20 to +70 °C, with storage and transport range of -25 to +80 °C. Shock resistance per EN 60721-3-7 Class 7M2 (500 m/s²), vibration at 200 m/s².
Sourcing and lifecycle reality
The MTBF is listed at 430 years, which reflects the solid-state design with no moving parts. In practice, the limiting factor is the connector and cable assembly in washdown environments, not the electronics. The IP67 rating means the reader body and optics survive hose-down cleaning, making it suitable for food-and-bev or automotive production lines where ISO 15693 tags are already in use.
Integration notes
Mounts with two M5 screws through the 50 x 50 mm face — no DIN rail option, so plan for a bracket or direct panel mount. The M12 connector is a standard 4-pin A-coded IO-Link socket; wire per the master's pinout (typically pin 1 = L+, pin 3 = L-, pin 4 = C/Q). Keep the cable run under 20 m to stay within IO-Link V1.0 spec. The reader is not multitag-capable and handles one transponder at a time. For applications requiring simultaneous reading of multiple tags on a pallet or tray, this is not the right part — look to the RF600 series for that. The 40 ms per-byte access time means a full 8-byte read takes about 320 ms; factor that into your cycle time budget.