The 0–10 measured output voltage from the RP-C’s Ub terminals may not provide the expected voltage.
EcoStruxure Building Operation
SmartX Controller RP-C
On the RP-C controller's the Ub return terminals although internally connected to each other are isolated from ground (-).
Add a ground reference connection between ground and one of the return terminals of the controller.
Example if the controller is stand-a-lone using terminal 3, which is an isolated terminal and can be used for the connection.