Building Automation System
WME Controls provides our customers with custom temperature control solutions. Whether your application is a simple programmable thermostat or a complex campus wide comprehensive building automation system, we can provide a system tailored to your individual project requirements. Our systems include a user friendly web based graphical user interface that allows for easy occupied/unoccupied scheduling as well as providing necessary information for maintenance personnel to properly monitor system operation. Alarms can even be communicated to mobile devices. We are authorized business partners for Johnson Controls Facility Explorer and Distech Controls. Our technicians are Niagara certified and experienced in BACnet and Lonworks network systems. Please call or contact us through our website for more information.
Building Automation System Diagram
A building automation system (BAS) uses interlinked networks of software and hardware to monitor and control a building’s mechanical and electrical systems, including heating, ventilation and air-conditioning (HVAC), lighting, security and fire systems. From a physical perspective, the BAS consists of Servers, Supervisory Devices, Field Buses, Controllers, Inputs and Outputs.
BAS Main Components
Building Automation Systems can be implemented either during initial construction or through a retrofitting process for an existing structure. It uses five component categories to provide a smart building environment.
Servers are machines that collect and serve up the BAS data. These servers will either take the form of a desktop machine or a rack-mounted server. These servers will run the BAS software and will connect to the network using network interface cards (NIC)
Supervisory devices can be either software or hardware based. Software supervisory devices are often known as soft-supervisors, where the supervisory software exists inside a server instead of a dedicated device, are becoming more common.
Soft-supervisors will utilize communication cards so that they can communicate with field buses.
Physical supervisory devices, where the supervisory device software is installed in a dedicated device, are still the most common devices. These devices will typically have an Ethernet NIC and a field trunk port (to connect field buses).
Field buses are the way building automation field controllers communicate back to supervisory devices. There are two prominent field buses right now. These are BACnet MS/TP and LON FT-10. These field buses connect field controllers back to the supervisory device using a daisy chain architecture.
If you're wondering what a daisy chain architecture looks like, just picture a set of Christmas lights. Each light is connected to the other light in a chain of lights. This is what modern field buses look like.
The supervisory device that connects these field controllers together will send messages across the field bus and will receive messages from the field controllers on the network.
Controllers are potentially stand-alone devices that control systems. An example of a system would be an air handler unit or a central plant. These controllers are programmed using programming software.
This programming software is usually specific to each individual vendor and can only be used on their field controllers.
There are two main types of field controllers:
Free programmable field controllers are able to be freely programmed. I know you're like "thanks, Phil that helps a lot...". Seriously though, back in the day, you couldn't configure a field controller. Nowadays you can log into a field controller and configure it to perform any control sequence you want it to.
On the other end of the spectrum, you have application specific field controllers. These controllers are specific to a single application. You cannot program these controllers you can only adjust preprogrammed settings.
Inputs / Outputs
A BAS controller will take signals from inputs (things like pressure or temperature sensors).
Then the program inside the controller will decide to do something based on the value of these inputs.
Once that thing action is determined the BAS controller will command an output (actuator, relay, etc).