The solution we adopted: Configuration of Python Plugin:

self.api.exchange.get_actuator_handle(
     state, "System Node Setpoint", "Temperature Setpoint", "Condenser Tower Outlet Node")

Changes in the IDF: IDF: * removed the Setpoint Manager SetpointManager:CondenserEnteringReset:Ideal

SetpointManager:CondenserEnteringReset:Ideal,

Result: It's working smoothly. We can change the setpoint via Plugin and the setpoint is followed.