SCADA Vs BMS (BACNET)
SCADA Vs BMS (BACNET)
(OP)
In the application of district cooling plants, which system is better to control and monitor the process of producing chilled water and the distribution on the buildings Heat Exchanger Rooms. SCADA or BacNet BMS system?





RE: SCADA Vs BMS (BACNET)
I use either a tradiction PLC or DCS type of control systems.
"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?
RE: SCADA Vs BMS (BACNET)
I know that Scada system with PLC controllers are much more accurate and reliable and it is used widely in the industrial processes. My question was, in the application of the chilled water system (where buildings will be connected to District Cooling Plants through a fiber optics Wide Area Network) which system can be more efficient and feasable?
RE: SCADA Vs BMS (BACNET)
I'm slightly bemused by
Most if not all DCS manufacturers would take issue with that concept. Both DCS and PLC technologies are very reliable and capable of excellent performance when the application software is well designed.
----------------------------------
Sometimes I only open my mouth to swap feet...
RE: SCADA Vs BMS (BACNET)
First what level of accuracy are you looking for? If you are looking for extremely accurate temperatures and flows then you will need to think about your sensors and field devices first.
Who will be running the plant once it's built? SCADA is very difficult to mainatain and program and extremely expensive. We just installed a panel for LADWP that makes a fan kick into high speed and open a damper on three AHU's when it's too hot. It's all Allen-Bradley with a color tough screen. This is no lie - it's a $ 42,000.00 thermostat.
So here's the deal. First you need to figure out what type of front end you want (The black box that provides the interface to the PC). This will be an ethernet connection. Don't worry too much about speed as you are not running a printing press.
Second figure how you want to control everything and what end devices you want (valves, sensors etc.).
Now decide how "open" you want the system. If you want all of the controllers to communicate via Lonworks or BACNET then you would probably have a traditional HVAC controls contractor doing the installation.
If you decide you want Modbus as the communications medium or something else, then you could expect an electrical contractor with a System Integrator to do the work. My concern is that district cooling doesn't need to be too complicated. I would think the traditional controls HVAC controls route would work for you. Industrial System Integrators are great at designing rocket ships.
Consider a front end system like Tridium. It can handle Lonworks, BACNET and Modbus along with a few other protocols in one box.
RE: SCADA Vs BMS (BACNET)
RE: SCADA Vs BMS (BACNET)
HVAC sytems don't normally require high processing speed, which is usually provided by PLC's. In addition to that, DCC BMS systems are easier to program, operate and maintain.
RE: SCADA Vs BMS (BACNET)
RE: SCADA Vs BMS (BACNET)
As far as durability, I've seen both flake out. For that application and cost, I'd recommend a BMS solution, but not from my former company.
RE: SCADA Vs BMS (BACNET)
RE: SCADA Vs BMS (BACNET)
Most of the DCS manufacturers offer a 'one-stop-shop' to automate a process, providing hardware, software and application expertise. The PLC integrators have done a good job catching up, but a PLC solution will still typically pick and choose from third party vendors. This introduces risk in the eyes of those financing the build of traditional high capital value like power plants, risk which is perceived to be lower if a turnkey contract can be awarded. Note the use of 'perceived'; I am convinced that many DCS vendors owe their survival in part to this risk-averse attitude.
----------------------------------
Sometimes I only open my mouth to swap feet...
RE: SCADA Vs BMS (BACNET)
Mixing third party products is risky but the risks can be reduced by carefully evaluating specifications and completely bench testing the system.