# Modbus page ### **Modbus** Modbus devices are connected to terminals **15 and 16**. *** ### **Modbus Settings for RFTC-3** RFTC-3 operates as a **Modbus Master** for controlling FCU or heating units. The Modbus settings allow configuration of communication parameters and the list of connected devices. #### **Modbus Setting** This section allows you to configure the basic communication parameters according to the requirements of the connected unit: * **Baudrate** – Transmission speed * **Parity** – Parity check * **Stop Bit** – Number of stop bits After setting the values, confirm the changes by clicking **Change**. *** #### **List of Modbus Devices** This section lets you add or remove Modbus devices. Options: * **Add device** – Add a new device * **Delete device** – Remove an existing device When adding a device, enter the following: * **Slave ID** – The device identifier in the Modbus network (found in the device's documentation) * **Description** – A user-friendly name for easy identification **Registers for control:** * **ON/OFF** – Register to turn the device on or off * **Set Temperature** – Register for setting the desired temperature (with appropriate multiplier) * **Fan Speed** – Register for controlling fan speed (with specific regulation sequence) * **Mode** – Register for changing between heating/cooling modes (with appropriate switching logic) * **Swing** – Register to control louver movement > **Note:** Not all fields are mandatory. They can be activated using the parameter `activation=ON`. Only one unit can be configured and connected this way. Refer to the documentation of the connected devices for all required setup details. *** ### **Control** * **ON/OFF** – Can be controlled from the RFTC-3 display via the ON/OFF button * **Set Temperature** – RFTC-3 sends the desired temperature to the unit * **Fan Speed** – RFTC-3 sends the desired fan speed * **Mode** – Controlled via the "Mode" button on the display * **Swing** – Remains active if `activation=ON` *** ### --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://wiki.inels.com/inels-home/inels-wireless/devices/inels-wireless-heating-temperature-control/thermostats/rftc-3/modbus-page.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.