bms Protocol is a set of rules and guidelines for communicating data.Rules are defined for each step and process during communication between two or more Controllers. Networks have to follow these rules to successfully transmit data.

Current generation BMS systems are now based on open communications protocols and are WEB enabled allowing integration of systems from multiple system vendors and access from anywhere in the world.

Theses standards, such as BACnet and LonMark™, will make in-depth integration of products and systems from multiple vendors, and from multiple industries, much easier resulting in lower cost and more functional integrations.

BACnet 0r Building Automation & Control network

A data communication protocol for Building Automation and Control Networks ; developed by ASHRAE. To standardize communications between building automation devices from different manufacturers. BACnet allows for interoperability of devices and systems from various vendors allowing data to be shared and equipment to work together easily.

BACnet bms protocol networks supported :

• Ethernet
•   BACnet/IP
•   MS/TP (master-slave / token passing RS-485)
•   PTP  (serial communications, dial-up)
•   ARCNET
•   LonTalk  (in “foreign frames”)

Communications protocol is an essential element of the BMCS configuration due to the amount of data transferred from one point to another and because distributed processors may be dependent on each other for data pertinent to resident programs. Communications links, or buses, generally use either a poll/response or a peer protocol. Early BMCSs use pollresponse
protocols where most system intelligence and data processing was at the central processor. In the mid 1990s most BMCSs use peer protocols which share the communications bus equally among all bus devices with no master device.

Communications Protocol: A set of conventions used to govern the format and content of messages between processors.