twin wire with shielded cable

[Tesla]

Hi guys
First up this topic should be in the controls section.
Frikkie You are right, we can and do on some systems send data over power. In NZ some domestic hot water systems switch off and on from signals an the power line, called the ripple system. Not sure why we don't use it more in controls. I am working on a new system using the Arduino controller and will try to incorporate this function to save wiring - the idea is to use smart sensors and all I/O so as to communicate to blocks and sub blocks with LAN (not sending out 0 - 10v) but communicating to an address and sub address with data. Have become very busy at work though
Hi Al with most newer units of the same brand will either have a lon (echlon) chip on the controls board or lan for such a purpose to communicate off/on and a limited amount of other points. Here you can daisy chain a bunch of units on site and connect them up to a HLI like tridium, opc which can then relay this data to a BMS. I only know of one person who has done it.

[assailant]

Hi guys
Frikkie You are right, we can and do on some systems send data over power.

hitachi 2.5 and 3.5kW wall splits only use a 2 wire 35VDC interconnecting for power and comms between indoor and outdoor unit.