PROFIBUS repeater for extended segments
The Siemens 6AG1972-0DA00-2AA0 is a PROFIBUS RS-485 repeater that regenerates signal amplitude and timing on long bus segments or star topologies. It supports the full PROFIBUS transmission rate range from 9.6 kbit/s to 12 Mbit/s, so it fits both legacy 187.5 kbit/s networks and high-speed 12 Mbit/s lines without reconfiguration. Rated for 24 VDC supply with a permissible range of 20.4 V to 28.8 V, it draws 30 mA typical. The supply and PROFIBUS cables both terminate on screw terminal blocks — no special bus connector required, which simplifies field wiring in a panel.
Wide temperature range and environmental resilience
Operating temperature spans -40 °C to 70 °C, making it suitable for unheated enclosures, outdoor cabinets, or cold-chain environments. Altitude derating follows a three-step curve: full temperature range up to 2 000 m, then a 10 K reduction from 2 000 m to 3 500 m, and a 20 K reduction from 3 500 m to 5 000 m. For a high-altitude installation at 3 000 m, the maximum ambient drops to 60 °C. The unit carries conformal coating per IPC-CC-830A Class A and is qualified against ANSI/ISA-71.04 for corrosive gas (Level GX Group A/B), salt spray (LC3), and oil (LB3) — useful for installations near chemical processing or coastal environments.
NRND — sourcing and replacement path
The 6AG1972-0DA00-2AA0 is classified NRND (Not Recommended for New Designs) by Siemens. For new designs or long-term spares planning, the standard Siemens PROFIBUS repeater (the 6ES7972-0DA00-0AA0) is the closest functional equivalent in the S7-300 ecosystem — same 12 Mbit/s rate, same 24 VDC supply, same screw-terminal wiring. The 6AG1 variant adds the wider temperature range and conformal coating; if those environmental margins are not required, the 6ES7 variant is the direct drop-in.