Modbus communication in AQ-200 series IEDs

Modbus communication in AQ-200 series IEDs

AQ-200 series devices can communicate using both Modbus RTU serial protocol and Modbus TCP protocol. Same data can be accessed using both these protocols.
To use Modbus TCP it can be activated with parameter Modbus TCP enable in menu Communication à Protocols à Modbus TCP.
Modbus RTU can be activated with parameter Protocol in menu Communication à Connections.
Data accessible via Modbus in AQ-200 series can be viewed in the Modbus map. The map can be opened from ToolsàCommunicationàModbus Map in Aqtivate setting tool. Modbus map can be saved into a text file with Save-icon.

In the map Modbus data is arranged in registers, HR stands for Holding Register and one register is 16bits. Some data in a protection relay does not map directly to 16bits, therefore there is data that requires more than one register in the map.

Modbus configurator

This tool is used to make changes to the register map when communicating using a Modbus protocol. It can be found at Tools > Communication > Modbus configurator. New modified map can be done by copying the needed rows by dragging from the default map into configurable map and then choosing the wanted holding register for the signals. Full description of the tool can be found in AQtivate instruction manual (downloadable at

Tool for testing modbus communication

AQwire is a free software developed by Arcteq which can be used for testing Modbus communication. Download the instruction manual and the software at Downloading the software requires you to be logged in.