CONN-MAX485
Module MAX485 RS485 TTL
Adaptateur TTL ↔ RS485 half-duplex — essentiel Modbus RTU.
Technical analysis
The MAX485 is the bridge between the 3,3/5 V world of a microcontroller and the industrial RS-485 bus: differential, noise-resistant, up to 1200 m and 32 nodes. It is the basic building block for speaking Modbus RTU to a PLC, a drive or an energy meter — the most widespread wired language in the factory.
To know: RS-485 is half-duplex, you must drive the direction (DE/RE) at the right moment, and the bus requires correct termination (120 Ω) and biasing on pain of corrupted frames. It is not plug-and-play, but it is reliable and documented. The retrofit guide shows how an ESP32 + MAX485 replaces a commercial gateway costing several hundred euros.
Verified specifications
Every figure below is sourced from the manufacturer datasheet.
- Topology
- RS-485 / RS-422 half-duplex transceiver
- Max guaranteed data rate
- 2,5 Mb/s
- Nodes on the bus
- up to 32 unit loads
- Supply
- 5 V single
- Common-mode range (reception)
- −7 V to +12 V
References & standards
📄 Official manufacturer datasheet — Analog Devices (ex-Maxim)
Applicable standards
- TIA/EIA-485 — Differential physical layer to which the component conforms (32 loads, common mode).
- Modbus RTU — Common industrial application protocol carried over RS-485; the MAX485 is a typical transceiver for it.