This document is the Modbus Communication Manual for the ATV12 variable speed drive. It describes the configuration, functions and application examples for Modbus communication.
This manual provides safety information, installation steps and detailed configuration guidance for the Altivar 12 variable‑speed drive. It covers the Modbus socket, RS485 wiring, and the parameters needed to integrate the drive into a Modbus network.
Key sections include safety warnings, connection diagrams, Modbus serial‑port settings, function codes, the ATV12 state machine, and an application example. The document also lists technical limits such as bus length, number of stations and recommended termination components.
| Maximum RS485 bus length | 1000 m at 19200 bps |
|---|---|
| Maximum number of stations | 32 stations (31 slaves) |
| Maximum tap link length | 20 m for one tap link |
| Pull‑down resistor value | 450 Ω to 650 Ω at 5 V |
| Line terminator | 120 Ω resistor in series with 1 nF, 10 V capacitor |
The bus can be up to 1000 m long at 19200 bps when using Schneider Electric TSX CSA cable.
Up to 32 stations (31 slaves) can be connected without a repeater.
Disconnect all power, lock the disconnects, wait 15 minutes for capacitor discharge, and verify the DC bus voltage is below 42 V.