What is a communication protocol for Building Management System - BMS?

Dear friend,

I am known with two protocols which is used for BMS System are BACNet & LONWorks &  i am using both for BMS system.

When a master controller is exchanging data with devices and meters within a building, the standard BACNet or Modbus or any other standard protocol should be preferred.  Otherwise, make sure it is at least “open” for anyone to read and write information.

bacnet ,lontolk, knx and mach more

use many protocol 

mainly is BACnet over IP and there are different protocols such as MODBUS & LON 

For Building management system (BMS) there are two protocols used which are BACnet and KNX. But mostly industry prefers BACnet Protocol. 

- Communication protocol mostly used for BMS application are BAC net ( Building Automation Controller network ),LONtalk ( Local Operating Network ), Modbus.

BACnet Protocol is common standard and following  MODbus   and MBus.

It's a rules for connection, communication and data transfer between devices. It's just because a site may have building automation system and control equipment from multiple manufacturers in the field, although there are ways to interconnect products made by different manufacturers without a standard protocol but it's very hard and very costly. The ISO made the 7 well known OSI layers as a fundamental model for any protocol.

BACnet is a protocol used to control bms systems communications

BACNet (Building Automation Control Network)

The communication protocol is usually different for each manufacturer, but the most commonly  used are MODbus, LONbus and BackNet. These protocols usually utilize a separate 2 or 4 core cable for the interconnection of their devices. When the direct connection between some components or subnetworks is now possible, a gateway that provides access to the building's LAN network, translating (encapsulating actually) the e.g. MODbus packets to be transferred through the TCP/IP network. Hence, you may see that the used protocol is MODbus/TCP-IP.