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The Ultimate Guide to Building Automation | Toronto

Building Automation is the automatic, systematic monitoring and centralized control of a building’s infrastructure. Building Automation System (BAS), also known as Building Management System(BMS) are the ways that use the advancement of Information Technology (hardware & software) in aspects of building operations. Such functions are, Mechanical, Electrical, Heating & Ventilation and Air conditioning (HVAC), Security, Life Safety, Lighting, Utilities, Telecom, and Energy Management of the building. These are independent entities, however, they are related to each other to operate. The objective of building automation is to create Smart and Intelligent building that will improve occupants comfort, efficient operation of building systems, reduction in energy consumption and operating costs, and improved life cycle of utilities.


For easy understanding, here are examples of common Building Automation,

  • In the hotel industry. Empty rooms usually are not ventilated or lit so as to reduce energy usage. When the occupants enter the rooms using the hotel key cards light automatically opens.
  • The use of Smoke detectors that are placed along with ceilings or high on walls which has the ability to identify a fire while it is still in its incipient. Alarms & later the sprinklers may be activated automatically.
  • Installation of Programmable thermostat in different parts of the building. It can automatically control to switch on air in rooms that are occupied, switch off during off-peak hours as well as to program desired setpoints.

To provide anything you need to know, whether your planning into the transition of your traditional building into an automated building or eyeing maintenance and upgrades for your smart or an Intelligent buildings, Here are the ULTIMATE GUIDE in Building Automation.

How Building Automation works

Components of Building Automation

  1. Communications Bus

 A contraction of the Latin omnibus [1] is a series of wires connecting field controllers to one another and to the supervisory device. This is a pathway for digital signals to rapidly move data.

Most building automation networks consist of a primary and secondary bus which connect high-level controllers with lower-level controllers.

  • 1. Primary Bus

Connects sensors and actors (up to 64 devices on the bus) with a central control unit.

  • 2. Secondary Bus

This is optional, connects up to 8 central control units, a GSM unit or  a unit of

Logical functions. TCP/ IP modules or other high-end devices.

2. Communications Protocol


Sets of Rules for how messages are formed and transmitted across the wire. These are needed to facilitate the control functions to specify control system capabilities on data collection, archiving, networking, remote annunciation. These mainly used for the automation process.

  • 2.1. BACnet ( Building Automation & Control Network)


[2]A Data Communication Protocol for Building Automation and Control Networks.

Developed under the auspices of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), BACnet is an American national standard, a European standard, a national standard in more than 30 countries, and an ISO global standard. [3]It was designed to allow communication of building automation and control systems for applications such as heating, ventilating, and air-conditioning control (HVAC), lighting control, access control, and fire detection systems and their associated equipment. The BACnet protocol provides mechanisms for computerized building automation devices to exchange information, regardless of the particular building service they perform.


  • 2.2. Modbus


A network protocol best used for industrial automation systems specifically for connecting electronic equipment. Developed under Modicon Inc. and standard maintained by Modbus Organization, Inc [4] It is an application-layer messaging protocol to provide client/server communication between devices connected on different types of buses or networks.


  • 2.3. LonWorks (Local operating netWorks)

 [5]An open platform for connecting building systems to each other and the Internet.

The system consists of the LonTalk communication protocol, a dedicated controller (Neuron Chip) and a network management tool.

It was designed on low bandwidth, for networking devices through power lines, fibre optics, and other media. Developed by Echelon Corporation(Motorola).

 Systems Architecture of BACnet [6]


3. Controllers

 BAS Controllers are purpose-built computers with input and output capabilities, it was considered as the “brain” of Building Automation System. It has two main processes, the Input, which takes the data from the sensors and decide how the system will respond. The outputs, that allow the controller to send command and control signals to slave devices, and to other parts of the system.

Categories of Controllers


  • 1. Programmable Logic Controllers (PLCs)

[6]A digital computer used for industrial automation to automate different  electro-mechanical processes. These controllers are specially designed to survive in harsh situations and shielded from heat, cold, dust, and moisture etc. PLC consists of a microprocessor which is programmed using the computer language.


  • 2. System/Network controllers, and Terminal Unit controllers

It can be applied to control one or more mechanical systems such as an Air Handler Unit (AHU), boiler, chiller, etc., or they may supervise a sub-network of controllers.


  • 3. Terminal Unit controllers

Are suited for control of lighting and/or simpler devices such as a package rooftop unit, heat pump, VAV box, fan coil, etc. The installer typically selects one of the available pre-programmed personalities best suited to the device to be controlled, and does not have to create new control logic.

 4.Input and Output devices

4. 1. Sensors

Analog inputs are used to read a variable measurement. A digital input indicates if a device is turned on or not – however it was detected. They capture the measurements that are sent to the controllers to be processed by the system.


Examples of Sensors

  • Room temperature sensors
  • Outdoor temperature sensors
  • Immersion temperature sensors
  • Brightness sensors
  • Air quality sensors
  • Pressure sensors

4.2. Controls

Analog outputs control the speed or position of a device. Digital outputs are used to open and close relays and switches as well as drive a load upon command.

Examples of Controls

  • Variable frequency drive
  • I-P (current to pneumatics) transducer
  • Valve or damper actuator

Layers of Building Automation [7]

  1. Server/Application Layer

It consolidate data from multiple different supervisory devices. It then delivers this data to the end user through the user interface (UI), often known as clients.  Also store trend, alarm, and schedule data in a database.

  1. Supervisory Layer

This is where the supervisory devices sit. Supervisory devices collect all of the traffic from the field controllers and consolidate this traffic.These devices serve to manage your communication trunks. Communication trunks allow your field controllers to connect to one another and allow your supervisory devices to collect information from the field controllers.

  1. Field Controller Layer

Look at data from inputs (temperature sensors, switches, etc) and then control outputs (actuators, relays, etc). BAS companies will use programming tools (usually developed by the BAS vendor) to program these field controllers.

  1. Input/Output Layer

This is where the sensors and control devices exist. There isn’t a ton to add here except that you are starting to see IP-enabled sensors that use Ethernet or Wi-Fi for their communications.

Systems, Networks & Integration[8]

On this section, we will discuss the ways in which components are linked together to form a complete Building Management System (BMS).

  1. BMS Architecture

[9]High-level organizational description of the elements that make up a building management system. These elements vary greatly from building to building, depending on the business objectives of the property managers or building owners.

  • 1. Conventional Controls

Controllers are based on analogue inputs & outputs, usually used in smaller buildings. Each controller are based on operational amplifiers (now replaced by microprocessors) and linked by direct connection to the controlled output device and perform single function. Several independent control systems may coexist within the building.

  • 2. Centralised Intelligence

From the use of microprocessors, it was developed to Direct Digital Control (DDC) Systems. The controller function is carried by software program, which can be program to execute to any desired control characteristic. Many control loops can be handled by the same processor. Control function can be made by changes to software alone.Without any change in the hardware.

  • 2.1. Dumb outstation

Separate wiring for each sensor and actuator is expensive and this has led to introduction of  local outstations ( Data Gathering Panels). Sensors are connected in to the outstation which performs signal processing and communications functions.


  • 3. Programmable Controllers

While the use of dumb outstations reduces the wiring requirement for the large BMS, it is vulnerable for CPU failure. The programmable controllers or intelligent outstations are developed, which incorporate their own microprocessor and carry out local control functions which will operate in the event of CPU problem. Devices communicate via a local area network or bus.

  • 4. Bus Systems

Decentralisation is carried further, where the intelligent devices in the control system incorporate in their own microprocessor and communications ability. Devices are connected to a bus which allows communication between all devices using well-defined protocol. Each device is individually addressable and programmable.

  • 5. Modular system

The system uses a range of modular units, each of which is programmed to control specific item. There is a range of zone controllers which perform the function of local user interface. All the modules communicate thru twisted-pair bus system using the Lontalk protocol.

  • 6. Package system

A package unit complete with factory installed unitary control system. It is set directly to the local controller then to the main BMS for the purpose of time scheduling and transmitting of alarm system. Each unit will control itself independently. This is often considered as economical.

 [11] Hierarchical structure of communication level

Field Level

This is the bottom part of the system, where the sensors and actuators are installed. It controls the devices in the building.

 Automation Level

 The mid part of the system, where the data from the field level are received and linked with each other via the application software of the components to enable the system to function.

 Management Level

 The top part of the system, where the data are processed and visualized. The user himself is able to step in and change operating parameters. Additionally, it is possible to record, protocol and configure data.

 Internet of Things(IOT) in Building Automation

 Is an advance building automation system which uses analytic software & services. The data sent between devices and to cloud, which is more secure, manageable & user friendly. It connects people with technology. This is a network of sensors, meters, appliances, and other devices that are capable of sending and receiving the data.

 [12]Four categories


  1. Energy

Includes popular applications like wireless energy consumption monitoring.

  1. Equipment

Those that optimize lighting and HVAC use.

  1. Environmental quality

Devices might measure particulate matter or CO2.

  1. People or spaces

Devices that can measure occupancy, space utilization or how many people have passed through a certain entrance.

Plan to jump in,  into IOT from traditional building? We’ll be glad to help, feel free to Contact us.


  1. https://buildingautomationmonthly.com/what-is-a-communications-bus/
  2. http://www.bacnet.org/
  3. https://en.wikipedia.org/wiki/BACnet#cite_note-1
  4. http://modbus.org/
  5. https://www.researchgate.net/publication/281903357_Latest_trends_in_building_automation_and_control_systems
  6. https://www.engineersgarage.com/article_page/plc-an-overview/
  7. https://buildingautomationmonthly.com/building-automation-system/
  8. https://study.com/academy/lesson/building-management-system-architecture-trends.html
  9. https://www.slideshare.net/AYM1979/building-control-system-aplication-guide-cibse-guide
  10. http://iotbacnet.com/products/airtek/
  11. https://www.dial.de/en/blog/article/bus-systems-for-smart-buildings-a-comparison-of-open-systems/
  12. https://www.buildings.com/news/industry-news/articleid/21603/title/iot-smart-building-technology