This document provides the Modbus communication manual for Schneider Electric Altivar 312 variable speed drives, including topics such as connection to RS485 bus and Modbus protocol.
This manual provides the information needed to connect the Altivar 312 drive to an RS485 bus and configure its Modbus communication parameters. It includes safety notices, wiring guidelines, and recommended cabling practices for reliable operation.
The document describes the Modbus serial port settings, supported baud rates, address range, and network topology limits, as well as the Modbus RTU protocol specifics and non‑standard RS485 schematics for special installations.
| Modbus address range | 1‑247 |
|---|---|
| Supported baud rates | 4.8, 9.6, 19.2 kbps |
| Maximum bus length (standard schematic) | 1000 m at 19200 bps |
| Maximum number of stations (without repeater) | 32 (31 slaves) |
| Line terminator value | 120 Ω with 0.25 W resistor and 1 nF capacitor |
The standard schematic allows up to 1000 m of bus length at 19200 bps.
The drive supports 4.8 kbps, 9.6 kbps and 19.2 kbps baud rates.
Up to 31 slave devices (32 stations total) can be connected.
A 120 Ω resistor (0.25 W) in series with a 1 nF, 10 V capacitor is recommended.