Technical Note — Schneider Electric Altivar 61

Rowan Chase

Created: ; updated: .


The Observant C3 Platform can remotely control and monitor the Schneider Electric Altivar 61 Variable speed drives for synchronous and asynchronous motors.

The installation of the VSD is not detailed in this article, installation should be carried out by a qualified electrician.  This article focuses on the interface between the Observant C3 and Schneider Electric Altivar 61.  Observant will provide support ONLY for the C3 configuration (though note that the MODBUS map below MUST be followed).

Remote control capability should not replace local on/off control or any other fail-safe hardware. An Emergency Stop button and appropriate power disconnects should always be in place at the same location as the VSD.


As part of an Observant system, the device can show:

  • Status
  • Pressure
  • Faults
  • Energy Consumption
  • Output Frequency
  • Pressure Setpoint
  • Drive Mode
  • Remote Mode
The VSD can be started and stopped remotely and the pressure set point can be adjusted. 
It can be scheduled via the Schedule App.
The VSD can provide SMS alerts on shutdown

Electrical Connection and Installation

Connection to the VSD is via the RS485 MODBUS connection located inside the front panel

The Observant field unit should be located as close as possible to the controller.  RS-485 comms to the Schneider Electric Altivar 61 is via a standard RJ45 4-way to Observant C3 terminal connector:

Connector terminal Function
1 Not Connected
2 RS-485 B (Observant B)
3 RS-485 A (Observant A)


System Protection

Please note that Observant do not take any responsibility for the safety and protection of the system.  This is assumed to be the responsibility of the VSD.  Any further protection requirements above those provided by the VSD are the responsibility of the installer.

 Configuring the Schneider Electric Altivar 61

The VSD acts as a MODBUS Slave device with the C3 as the Master.  The slave address, must be configured on both the C3 and the VSD.  By default the C3 will be configured to address 1.

The configuration of the VSD MODBUS register layout must adhere to the below:

Register Type Register Address MODBUS Function Register Offset (from 400001) Description
Read Holding 411982 3 11981 Actual Speed
Read Holding 408504 3 8503 Set Point
Read Holding  408604 3 8603 Status
Read Holding  407122 3 7121 Faults
Read Holding 405203 3 5202 Warnings
Read Holding  403203 3 3202 Motor Current
Read Holding  403238 3 3237 Running Total LSW
Read Holding  403235 3 3234  Running Total MSW
Read Holding  408504 3 8503  Set Point


External Links

Product Page

Installation Manual


Schneider Electric

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