ABSTRACT
A Building Management System (BMS) is a computer based control system installed in buildings that controls and monitors the building’s mechanical and electrical equipment in the most efficient way.
Benefits
• Switches plant on and off automatically according to time, time of day and environmental conditions (e.g. senses conditions and activates devices to correct settings)
• Optimizes plant operation and services • Monitors plant status and environmental conditions and thus improves standards of operation and main-
tenance • Allows remote access, control and monitoring (e.g. using graphical information and alarms)
Types of BMS points
• Is the physical connection of a BMS point to a controller or outstation I/O terminals? The points schedule is critical when designing the system
• Input – gathers data/monitor; Output – provide command/control • Analogue points – has a variable value 0% to 100% (e.g. temperature sensor, modulating control valves) • Digital points – binary I/O (0 or 1) (e.g. on/off control, run/off/fault status) • Network integration points (NI) – allows to communicate or integrate to stand alone controller such as chiller,
meters, boilers, generators
BMS components – hardware and software/programming
Hardware
• Primary network/BMS backbone - Head end equipment (desktop computer, laptop, monitors, keyboard, dot matrix and colour printer,
UPS supply, etc.) - Ethernet Network Cabling (normally Cat 5e or Cat 6 cables) - Ethernet switch (located inside the control panels)
• Secondary network - Control enclosure (CE) or Control panel (CP) or BMS outstation - Motor control centre (MCC) - Unitary controller for FCU/VAV/Chilled beams - Power cables and isolators (from MCC panel to mechanical equipments) - Control cables (from MCC/CE panel to field devices) - Field devices (control valves, meter, sensors, VSD/Inverter, DOL starter, star-delta starter, actuators)
Software/programming
• BMS programme protocol – Refers to the communication of BMS from PC software to the different types of controller/sensors (e.g. Modbus, LonWorks, BACnet)
• Graphics – Provide true representation of the installed plant. Colour graphics shall incorporate automatic updating of real time field data.
