Introduction to BMS - Revision history

AlexDriv at 00:40, 4 January 2026

2026-01-04T00:40:22Z

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	~~__TOC__~~

	= What is BMS? =		= What is BMS? =

AlexDriv at 00:31, 4 January 2026

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 When reviewing trends, it helps to overlay related values on the same graph. For example, comparing supply air temperature against setpoint and outside air temperature can quickly reveal whether control is stable or hunting.
 =Commissioning and handover=
 =See also=

AlexDriv: /* System architecture */

2026-01-04T00:29:50Z

System architecture

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	= System architecture =		= System architecture =
	~~'''~~A BMS is structured in layers, typically divided into field level, automation level, and management level. This hierarchy allows data to flow from physical devices up to a central interface where operators can monitor and control building services.~~'''~~		A BMS is structured in layers, typically divided into field level, automation level, and management level. This hierarchy allows data to flow from physical devices up to a central interface where operators can monitor and control building services.

			At the lowest level, field devices such as sensors, actuators, and meters are installed throughout the building to measure conditions and carry out control actions. These devices connect to controllers, which sit at the automation level and execute the logic that keeps systems running — adjusting valve positions, starting fans, and responding to changing conditions. At the top of the hierarchy, the head-end provides a central point of supervision where operators can view the entire system, acknowledge alarms, and analyse performance.

			[[File:BMS-architecture-diagram.png\|thumb\|center\|450px\|Typical BMS architecture showing field devices, controllers, and head-end]]

			This layered approach means that control happens locally at the controller level, so buildings continue to operate even if the head-end goes offline. The head-end is primarily for visibility and oversight rather than moment-to-moment control.

	== Field devices ==		== Field devices ==

AlexDriv at 00:28, 4 January 2026

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 =Graphics and user interface=
 ==Alarms and events==
 ==Trends and logs==
 =Commissioning and handover=
 =See also=

AlexDriv: /* System architecture */

2026-01-04T00:27:03Z

System architecture

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	= System architecture =		= System architecture =
	A BMS is structured in layers, typically divided into field level, automation level, and management level. This hierarchy allows data to flow from physical devices up to a central interface where operators can monitor and control building services.		'''A BMS is structured in layers, typically divided into field level, automation level, and management level. This hierarchy allows data to flow from physical devices up to a central interface where operators can monitor and control building services.'''

	== Field devices ==		== Field devices ==

AlexDriv at 00:26, 4 January 2026

2026-01-04T00:26:17Z

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	A communication protocol defines how devices and controllers exchange data within a BMS. Different protocols are used depending on the equipment manufacturer, system age, and project requirements. Understanding the basics of each protocol helps when diagnosing communication issues or integrating third-party systems.		A communication protocol defines how devices and controllers exchange data within a BMS. Different protocols are used depending on the equipment manufacturer, system age, and project requirements. Understanding the basics of each protocol helps when diagnosing communication issues or integrating third-party systems.

	The two most common protocols in modern BMS installations are BACnet and Modbus:		'''The two most common protocols in modern BMS installations are BACnet and Modbus:'''

	* '''[[BACnet]]''' — the industry standard for building automation, developed specifically for BMS applications. BACnet supports a wide range of network types including BACnet/IP for head-end communication and BACnet MS/TP for field-level wiring. It allows different manufacturers' equipment to communicate natively without the need for gateways, and provides standardised objects for common functions like analogue values, schedules, and alarms. One of the key advantages of BACnet is device discovery — when a BACnet device is connected to the network, the BMS can automatically detect it and retrieve a list of all available points along with their names, descriptions, and engineering units. This significantly reduces commissioning time compared to older protocols.		* '''[[BACnet]]''' — the industry standard for building automation, developed specifically for BMS applications. BACnet supports a wide range of network types including BACnet/IP for head-end communication and BACnet MS/TP for field-level wiring. It allows different manufacturers' equipment to communicate natively without the need for gateways, and provides standardised objects for common functions like analogue values, schedules, and alarms. One of the key advantages of BACnet is device discovery — when a BACnet device is connected to the network, the BMS can automatically detect it and retrieve a list of all available points along with their names, descriptions, and engineering units. This significantly reduces commissioning time compared to older protocols.
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	Other protocols you may encounter include:		'''Other protocols you may encounter include:'''
	* '''[[LonWorks]]''' — a peer-to-peer protocol found in some legacy systems and lighting controls		* '''[[LonWorks]]''' — a peer-to-peer protocol found in some legacy systems and lighting controls
	* '''[[KNX]]''' — common in European installations, typically for lighting and blinds		* '''[[KNX]]''' — common in European installations, typically for lighting and blinds

AlexDriv: /* Communication protocols */

2026-01-04T00:25:56Z

Communication protocols

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	* '''[[Modbus]]''' — a simple, reliable protocol originally developed for industrial control. Modbus is widely supported by third-party equipment such as meters, variable speed drives, generators, and packaged plant. It uses a register-based data structure where each value is stored at a specific address, typically shown as a number (e.g. register 40001 for a supply air temperature). To integrate a Modbus device, the engineer must manually configure each point by referencing the manufacturer's register map, entering the correct address, data type, and any scaling factors. This process is more time-consuming than BACnet but remains common due to the wide availability of Modbus-compatible equipment.		* '''[[Modbus]]''' — a simple, reliable protocol originally developed for industrial control. Modbus is widely supported by third-party equipment such as meters, variable speed drives, generators, and packaged plant. It uses a register-based data structure where each value is stored at a specific address, typically shown as a number (e.g. register 40001 for a supply air temperature). To integrate a Modbus device, the engineer must manually configure each point by referencing the manufacturer's register map, entering the correct address, data type, and any scaling factors. This process is more time-consuming than BACnet but remains common due to the wide availability of Modbus-compatible equipment.

	~~[[File:Modbus-register-map-example.png\|thumb\|right\|300px\|Example of a Modbus register map from a meter manufacturer]]~~

	Other protocols you may encounter include:		Other protocols you may encounter include:

AlexDriv: /* Communication protocols */

2026-01-04T00:25:34Z

Communication protocols

← Older revision		Revision as of 00:25, 4 January 2026
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	A communication protocol defines how devices and controllers exchange data within a BMS. Different protocols are used depending on the equipment manufacturer, system age, and project requirements. Understanding the basics of each protocol helps when diagnosing communication issues or integrating third-party systems.		A communication protocol defines how devices and controllers exchange data within a BMS. Different protocols are used depending on the equipment manufacturer, system age, and project requirements. Understanding the basics of each protocol helps when diagnosing communication issues or integrating third-party systems.

	~~Common~~ protocols ~~encountered~~ in BMS ~~include~~:		The two most common protocols in modern BMS installations are BACnet and Modbus:
	* '''[[BACnet]]''' — ~~an open~~ standard ~~widely used in commercial buildings~~, ~~supporting multiple~~ network types including IP and MS/TP
	* '''[[Modbus]]''' — a simple ~~and common~~ protocol~~, often used~~ for meters, variable speed drives, and packaged plant		* '''[[BACnet]]''' — the industry standard for building automation, developed specifically for BMS applications. BACnet supports a wide range of network types including BACnet/IP for head-end communication and BACnet MS/TP for field-level wiring. It allows different manufacturers' equipment to communicate natively without the need for gateways, and provides standardised objects for common functions like analogue values, schedules, and alarms. One of the key advantages of BACnet is device discovery — when a BACnet device is connected to the network, the BMS can automatically detect it and retrieve a list of all available points along with their names, descriptions, and engineering units. This significantly reduces commissioning time compared to older protocols.
	* '''[[LonWorks]]''' — a peer-to-peer protocol ~~used~~ in some legacy systems and lighting controls
	* '''[[KNX]]''' — ~~typically found~~ in European installations, ~~often~~ for lighting and blinds		* '''[[Modbus]]''' — a simple, reliable protocol originally developed for industrial control. Modbus is widely supported by third-party equipment such as meters, variable speed drives, generators, and packaged plant. It uses a register-based data structure where each value is stored at a specific address, typically shown as a number (e.g. register 40001 for a supply air temperature). To integrate a Modbus device, the engineer must manually configure each point by referencing the manufacturer's register map, entering the correct address, data type, and any scaling factors. This process is more time-consuming than BACnet but remains common due to the wide availability of Modbus-compatible equipment.
	* '''[[OPC]]''' — a software interface standard used to connect BMS with ~~other~~ enterprise systems and ~~historians~~
			[[File:Modbus-register-map-example.png\|thumb\|right\|300px\|Example of a Modbus register map from a meter manufacturer]]

			Other protocols you may encounter include:
			* '''[[LonWorks]]''' — a peer-to-peer protocol found in some legacy systems and lighting controls
			* '''[[KNX]]''' — common in European installations, typically for lighting and blinds
			* '''[[OPC]]''' — a software interface standard used to connect BMS with enterprise systems, historians, and other platforms

	[[File:BMS-network-diagram.png\|thumb\|center\|400px\|Example of a BMS network showing different protocols at each level]]		[[File:BMS-network-diagram.png\|thumb\|center\|400px\|Example of a BMS network showing different protocols at each level]]
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	For more detail on individual protocols, see the linked pages above.		For more detail on individual protocols, see the linked pages above.

	=Graphics and user interface=		=Graphics and user interface=
	==Alarms and events==		==Alarms and events==

AlexDriv at 00:22, 4 January 2026

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 =Communication protocols=
 =Graphics and user interface=
 ==Alarms and events==

AlexDriv at 00:21, 4 January 2026

2026-01-04T00:21:17Z

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	The head-end may be installed on a local server or accessed via a web-based interface depending on the system configuration.		The head-end may be installed on a local server or accessed via a web-based interface depending on the system configuration.

			=Communication protocols=
			=Graphics and user interface=
			==Alarms and events==
			==Trends and logs==
			=Commissioning and handover=
			=See also=