Building Management System (BMS) is a high technology system installed on buildings that controls and monitors the building’s mechanical and electrical equipment such as air handling and cooling plant systems, lighting, power systems, fire systems, and security systems. A BMS consists of software and hardware. The software program, usually configured in a hierarchical manner, can be proprietary using such protocols as C-bus, Profibus, etc. Recently however new vendors are producing BMSs that integrate using Internet protocols and open standards like SOAP, XML, BacNet, Lon and Modbus.
For example in an Organization BMS comprises of 'Access Control' (which controls the employees restricted movability in the Organization), CCTV facilities, etc.
Building Automation System
A Building Automation System (BAS) is an example of a Distributed control system. Building automation describes the functionality provided by the control system. The control system is a computerized, intelligent network of electronic devices, designed to monitor and control the mechanical and lighting systems in a building.
BAS core functionality keeps the building climate within a specified range, provides lighting based on an occupancy schedule, and monitors system performance and device failures and provides email and/or text notifications to building engineering staff. The BAS functionality reduces building energy and maintenance costs when compared to a non-controlled building. A building controlled by a BAS is often referred to as an intelligent building.