Building Automation Systems
Defining a Buildings Automation System
Building Automation Systems; BAS or Building Management System; BMS, utilizes various mechanical and electrical equipment to control and monitor a buildings HVAC, lighting power, fire alarm, security and energy management systems. The BAS gives a building the ability to control various equipment and monitor its values through controllers, otherwise known as a programmable microprocessor. The controllers, or the “brains” of the operation, can be programmed and left un-monitored while preforming each programmed task. They may also be programmed to be in a network, where there is a central workstation to control and monitor all controllers.
Figure 1 (BAS Network)
A building controlled by a BAS (BMS) is often referred as a “smart building”. The BAS responsibilities is to provide the building climate control at specific ranges based on scheduled time, provide lights to rooms based on occupancy, monitor performance and provide any alarms that will require the engineers attention. For most of the building automation networks, there is a primary and secondary bus line which connects high-level controllers with low-level controllers, input/output devices and a user interface device. The high-level controllers are usually specific building automation controller or can be generic programmable logic controllers that provide the full control of the system. The low-level controllers (also known as a human interface device) are the device and equipment in the field being controlled by the end-user.
The BAS Communication
The physical connections between these devices can vary depending on what is being installed. Most connections between devices can be a dedicated optical fiber, Ethernet, ARCNET, RS-232, RS-485 or a low bandwidth special purpose wireless network. There are a few communications protrocol for BAS networks but the most popular one being used is ASHRAE’s open protocol Bacnet.
| ASHARES BACnet | Building Automation Control Network developed by ASHRAE. |
| APOGEE FLN | Building Automation network developed by Siemens. |
| Metasys N2 | Building automation network developed by Johnson Controls. |
| LonWorks | An Echelon designed protocol designed widely used in building automation. |
What Equipment Does the BAS Control?
A BAS can control from old pneumatic systems to new IP systems, below is a list of equipment
- (HVAC) Heating ventilation and air conditioning
- Plumbing systems
- Central plant system
- Lighting and other electrical systems
- Fire alarm and other life safety systems
- Elevators and mechanical systems
- Security system
- Vents and exhaust fans
- VAV Boxes
The Benefits of a BAS
A few benefits of a configured BAS system is comfort in the building, efficient operation of the building systems, reduced energy consumption and operating costs.
The BAS provides the engineer the ease of changing the schedule remotely instead of configuring each thermostats and or unit directly. Once the system and
schedule has been configured the BAS goes to work maintaining temperature in spaces as per the engineers request.
A properly used BAS can save between 10% to 30% utilities bills. This can also help in maintain heavy pieces of equipment.
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