Modbus Mapping

After adding the Modbus device as described in the RTU Scan, the next step is to set up the register mapping. This involves creating bindings between Modbus registers and KNX group objects in the controller.

Follow these steps:

1. Navigate to the Modbus tab in the Configurator.

2. Each device in the list has a green mapping icon on the right side . Click it to open the Object mapping settings.

3. The Object mapping table represents each Modbus register (defined in the device profile).

4. Double-click a selected line or click the Map selected items to objects button to open the Mapping dialog.

5. Configure the following settings:

   • Link to object: Select the controller object where the value read from the Modbus register will be saved. You can choose an existing object from the dropdown menu or create a new one directly from this dialog.

   • Write to bus: Enable sending data to the KNX TP bus. If disabled, telegrams to KNX TP are not sent when the Modbus value changes. Telegrams are still sent to KNX IP. Properly configure the filtering table if you don’t want to share values through KNX IP.

   • Value send delta: Set the value of the delta. If the change in value read from the Modbus register exceeds this delta, the value is sent to the KNX bus. For KNX TP, ensure that the Write to bus option is enabled.

   • Unit/Suffix: Optionally set the unit of the Modbus value. This setting applies to the selected group object in the controller.

   • Tags: Optionally select a tag to apply to the group object in the controller.

   • Comments: Optionally select a comment to apply to the group object in the controller.