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Energy Management Control Systems
Published in Moncef Krarti, Energy Audit of Building Systems, 2020
To design a BACnet device, a manufacturer needs to identify the BACnet objects and services required to achieve the intended functionality for the device. A BACnet object is a standard data structure defined with a set of properties and data types. In its current version, the BACnet standard defines 20 objects such as loops, tables, schedules, commands, and programs. BACnet services are the programmed actions that use the data objects to achieve the function of the device. Services, defined by the current version of the BACnet standard, include alarm and event services (to notify of any alarm and event), file access services (to read and write files), object access services (to read or write the properties of objects), remote device management services (to troubleshoot and maintain devices), and virtual terminal services (to allow interaction between a terminal and the device). Moreover, the BACnet device has to conform to a set of specifications using a series of conformance classifications. Each conformance classification adds functional services to the device. Thus, each BACnet device design would have a protocol implementation conformance statement (PICS) prepared by the manufacturer to identify the BACnet options available in the device.
HVAC Control Systems
Published in T. Agami Reddy, Jan F. Kreider, Peter S. Curtiss, Ari Rabl, Heating and Cooling of Buildings, 2016
T. Agami Reddy, Jan F. Kreider, Peter S. Curtiss, Ari Rabl
BACnetTM (Building Automation and Control Network) is a standard communication protocol developed by the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE), which has been adapted by the American National Standards Institute (ANSI) and also by the International Standards Organization (ISO) as ISO-16484-5. BACnet (ANSI/ASHRAE Standard 135, 2012) is used in the control of HVAC (heating, ventilation, and air conditioning), building security, lighting, fire, access control, waste management, and other control equipment in buildings. Protocols are rules that need to be followed, which allow handling not only different types of signals and controllers but also the detection of bad data and facilitate quick data transfer. The main reason for the creation of BACnet was to enable building owners to use control equipment from different manufacturers without having to worry about interoperability.
Sensor Networking Software and Architectures
Published in John R. Vacca, Handbook of Sensor Networking, 2015
BACnet allows computer-based control equipment from different manufacturers to interoperate by providing a common control language. BACnet defines a standard set of "objects" to represent devices in the network. Each object has a standard set of "properties" that describe the object and its current status. An object may be controlled through its properties by other BACnet devices. BACnet defines 18 standard types of objects. One of the standard BACnet objects is the analog input object shown in Figure 15.2, which represents a thermistor. Some of the properties are set during installation or time of manufacture, while others provide dynamic status about the sensor input. All properties may be read, for example, a query about the Present_Value property of this analog input object would get the reply "68.0."
A data-driven predictive maintenance model for hospital HVAC system with machine learning
Published in Building Research & Information, 2023
Raid Al-Aomar, Marah AlTal, Jochen Abel
For data collection, field devices measure, collect the AHU’s sensor data and send signals to the DDC. The DDC processes the sensor data and transmits it to the Graphical User Interface (GUI) of BMS and CMMS database for condition monitoring and prediction. The databases is saved on a SQL server. Data collected from the field devices of AHUs include the temperature, pressure, CO2, and airflow sensor data in addition to unit name and location. Sensor data is sent to the DDC which converts them into numerical information and transmits them to the GUI of the BMS and the CMMS database. As shown in Figure 2, the DDC sends sensor data using the Building Automation Control Network (BACnet) protocol, which is designed to meet the communication requirements of the building automation and control systems such as HVAC, lighting, access, and fire detection control systems. The BACnet protocol provides mechanisms for computerized equipment with various functions to exchange information (ASHRAE, 2019). The data is transferred via a plug-in created and installed in the CMMS software to import and store data from the DDC. It should be noted that the attribute names of the imported data and the CMMS should match in order to facilitate the mapping of the imported data from the BMS to the CMMS system. The CMMS and condition databases are designed using the SQL data model and are stored on a server for centralized management. Data retrieval from the database is facilitated using SQL queries, a standard mechanism for requesting and processing specific data from relational databases.
Graph-based network generation and CCTV processing techniques for fire evacuation
Published in Building Research & Information, 2021
Jack C. P. Cheng, Keyu Chen, Peter Kok-Yiu Wong, Weiwei Chen, Chun Ting Li
To monitor the above-mentioned parameters, temperature sensors, CO2 sensors and CO sensors are required to be installed in target areas. The building automation and control network (BACnet) protocol, a data communication protocol among devices in various building systems (e.g. heating system, ventilation system, air-conditioning system, lighting system, etc.) (Newman, 1996) is used to obtain real-time data from each sensor. The obtained sensor data, including sensor identification (ID) and corresponding value is integrated into a database. In the database, sensors and the values of each sensor are assigned to corresponding edges of the graph-based network. For example, sensors installed in a corridor are assigned to the edges of the corridor so that the values of these sensors can indicate whether the edges are in a hazardous zone or not.