Figure 1: A Building Management System is key enabler of a 'Smart' or 'Intelligent' Building.

A Building Management System (BMS) (also known as a Building Automation System or BAS) is a control system that is used to control and monitor equipment so as to manage lighting, ventilation, heat, power, security and fire detection.The application domain of a BMS is very broad in scope and can include boiler room, pump and plant control, underfloor heating control, heat recovery systems and general process control. A BMS consists of hardware and software. Hardware will be used to control the equipment while instructions to these hardware components will be issued from a software system.

The common controls for equipment would be manual switches, time clocks or temperature switches. The purpose of a BMS is to automate these operations as much as is practicable. A BMS can be used for all kinds of buildings but would be most common in a manufacturing plant. Generally, the BMS will store a number of pre-set requirements for the building and controls the connected equipment to meet these requirements.

The hardware requirements for a BMS are diverse. Sensors including wireless sensors can be used to monitor temperature, humidity and even whether a room is occupied. Smart Meters can be used to monitor the use of resources such as gas, electricity and water. These devices can be controlled using Vertoda or can be interfaced with actuators to control mechanical moving parts. Heating, Ventilation and Air Conditioning (HVAC)  systems are generally controlled by SCADA (Supervisory Control and Data Acquisition) systems for coordinating operations. Distributed Control System (DCS) are complementary to SCADA systems in that they control operations and processes using a PLC (Programmable Logic Controller). Indeed, a Building Management System can be seen as a  particular example of DCS technology in action.

The PLC or actuator is just one example of an equipment controller that can be used by a BMS. System and terminal controllers are also available. In essence, these devices send control signals to the equipment to modify their calibrations or turn themselves on or off. Software is required to interface with these PLCs remotely and in many cases with non-PLC sensors and meters as well. One can see, therefore, that the diverse equipment and consequent standards means that a BMS is a complex platform from a software perspective that will require many monitoring and control components  for different equipment, buildings and conditions.

Generally, special protocols are used for BMS but this is beginning to change. BACNet (http://www.bacnet.org) is a data communication protocol used for building automation and control networks that was developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers. Lonworks is a platform created by Echelon (http://www.echelon.com) for enabling the creation of networks using devices that transport their data over diverse media such as twisted pair wire, power lines, fiber optics and RF (Radio Frequency). Modbus (http://www.modbus.org) is a open communications standard that is often used in SCADA systems. While these standards are quite specific in their intent we are beginning to see web protocols such as SOAP (Simple Object Access Protocol) and XML (eXtensible Markup Language) being used by BMS. As explored in a previous blog, different protocols are used to capture smart meter data while Zigbee is the prominent communications protocol used by Wireless Sensor Networks (WSNs). 

The key tasks of a BMS is monitoring and controlling equipment within a building or plant and providing reporting functionality on the performance of this equipment. A BMS can be used to detect equipment and plant faults, dirty or used filters as well as abnormal occurrences. A BMS can also provide details of energy consumption by different equipment and by different processes and operations that take place within the building. The results of energy saving initiatives can also be monitored with the BMS as can the consumption of gas, electricity and water. Measurements can be taken of different environmental conditions within the building such as temperature, humidity and air quality. Occupancy patterns of a building can also be monitored by a BMS and can assist in operational decision making regarding equipment.

Using the diverse hardware and communication technologies available a BMS can control all equipment within a building. Loads such as chilled water pumps can be turned off when not required. Lights and lifts can be turned off when the building is unoccupied. Peripheral controls such as occupancy sensors can relay this data to the BMS which in turn can send a control message to other equipment. A BMS can also play a key role in energy management by enforcing policies to reduce energy use during times of low occupancy e.g. automatically turning lights off when a room is unoccupied, turning off the air air conditioning overnight etc.

A BMS can be integrated into one unifed system with CCTV, Access Control, Energy Management and other voice and data systems to provide an overall system for managing building-wide operations. Data can be shared between these systems for security purposes and for detecting events such as fire in an isolated part of the building. A BMS is then a key component in what is often termed an Intelligent or Smart Building.

Given the myriad of equipment that needs to be monitored and controlled, many software systems can be required to make up one overall monitoring system. Vertoda can provide data capture and management for smart meters and wireless sensors among others. The latter devices in many cases are cheaper and more flexible alternatives to traditional sensors. The data captured by Vertoda is available to the other components of the Smart Building including the BMS. The fault management, Business Intelligence/Reporting and device management functionality of Vertoda can all be integrated into one unified solution for managing and controlling a plant or building with the consequent financial, security and energy saving benefits outlined above.