# Adding a Modbus RTU slave

You can add up to 32 slaves per master.

1. You must add a Modbus RTU master to your device configuration.

1. In the device tree, right-click on the master.
2. In the context menu, select Add device.

1. A new slave is added below the master. The lowest unused slave ID in the range of 1 to 247 is assigned to that slave. All slaves are sorted by their slave ID. The newly added slave remains selected.