Playing with your smart home is all fun until it also controls the heating ;) I use the temperature readout from my home-buttons as an external reference to control two heat pumps via node-red.  If the home-button fails (does not call for >35min) the PLC switches to the internal reference sensor. 

Most of the control logic happens on the PLC level. Only the communication with Mitsubishis melCloud takes place on the nodered.