# Retrieving the communication status of a Modbus RTU device

You can retrieve the communication status of Modbus RTU devices via status words. You can map status words to global variables in order to process them in an application program.

1. You must add Modbus RTU devices to your device configuration.

1. Open the global variables view.
2. Create a new global variable and change its data type to WORD.
3. Map the newly created variable to the desired status word. Choose from:

- Modbus RTU Client - [ID].Status Word: communication status of all servers connected to a client
- Modbus RTU Server - [ID].Status Word: communication status of an individual server

Creating a global variable

Changing the data type of a global variable

Changing the I/O mapping of a global variable

Description of the Modbus RTU status words