Time for a Leap-frog in HVAC Control System Technology
It’s been 15 years since the last major jump in HVAC control system technology. Back then it was the advent of open protocols that promised to revolutionize the industry. In many ways it did but in recent years we seem to have been falling back into some of the “old ways”, to the benefit primarily of the same control companies that were reluctant to open their systems.
And the battle between LonWorks based and BACnet based systems didn’t help either.
For someone who looks at those two protocols objectively and understands them, each has advantages and disadvantages.
BACnet MS/TP still uses RS-485 which has been around for a very long time and has some inherent issues: polarity sensitive, grounding, noise, and is not true peer to peer. Bandwidth is always an issue, setting up is tedious, troubleshooting can be a crap shoot and getting information from one device to another, especially on different channels is a challenge.
BACnet/IP much better than MS/TP but has it’s own issues: doesn’t support multidrop devices, need to add BBMP devices to get through routers, can give the IT department nightmares if too many broadcast messages and is still not true peer to peer (but at the speed of Ethernet it isn’t as much of an issue).
LonWorks FT is much more robust than Bacnet MS/TP / RS-485 but the information sent between devices is strictly the value and none of the other myriad pieces of information that can go along with the BACnet packet.
And none of these are future proof and support the upcoming push for the Internet of Things.
Here is a wish list:
- More robust than RS-485
- Can talk true peer to peer
- Supports IPv6 internet protocol
- Future proof
It’s here! Demonstrated at ASHRAE this year and we are installing it 2nd quarter.
The controllers will communicate simultaneously LonWorks, BACnet/IP, and a new internet-based protocol. The devices utilize the new IPv6 addressing and up to 64 devices can be on a single, twisted pair, daisy chained communication channel.
This gives us all the advantages without many of the previous disadvantages. The enemies have joined forces!