You can find me this week in Singapore. OK, honest now. Do you know where Singapore is?
Give up? It’s between the Vietnam and Thailand and Australia. It’s an island surrounded by Indonesia and Malaysia. An island with no natural resources that must import nearly 100% of its food, energy and every other consumable. It’s a great place but that’s not what I am writing about today.
I’m here working on a new University lab building. I’m part of a team integrating all the building systems. This includes Fire Systems, Access Systems, Elevators, Air Conditioning (it’s not HVAC here – 85°here every day) and Energy management.
So what did I find here? Well, a couple of things. One is BACnet. What’s BACnet? It’s a building automation industry standard network for moving data around a building.
Like CIP (the ODVAs Common Industrial Protocol) it’s object based. That means that every device on the network is composed of a bunch of objects that can be accessed by Client devices.
Unlike CIP there is no concept of an I/O message, there is only Explicit message support. Every data point must be accessed independently. Because most data changes infrequently this explicit only message support is acceptable. In a factory automation setting explicit only messaging would be death. Imagine having to interrogate a filling device to see how much liquid has been injected.
Another thing I find here is Metasys. Metasys is the high-level HMI from Johnson Controls. They’ve just released a new version and it’s really slick. Lots of cool new features but a bear to get your arms around. It’s also really expensive. $10K US. I asked my customer for a demo. No demo available. So I asked for a real copy. Uh, No John we’re not giving you $10K worth of software. (I’ve learned that if you keep asking someone will say yes.)
Of course, we found Modbus RTU here all over the building. Lot’s of automation devices have RS485 Modbus. Why you ask? Simple, every processor comes with a UART. A 485 transceiver is cheap. You can put it on a board for next to nothing along with a 3 pin connector (TxD, RxD and Gnd). And the code is easily obtained and small. You can run Modbus on any processor.
My earnest, naïve assistant Emily Brockman and I did get our end of things all straightened out and ship shape (she actually did all the work – she was the brains of out team and I was the “Eye Candy”, the “personality”). We left knowing a lot more about BACnet and putting Building Automation systems together.
Maybe in another report I’ll tell you some of my experiences outside the office. Most of the PG rated stuff anyway.