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Introduction to Digital Communication for Building Automation and DDC
Published in John J. “Jack” Mc Gowan, Energy and Analytics, 2020
The basis for data communication and network is protocol. A communications protocol is a system of digital rules for data exchange within or between computers, and those rules also establish the architecture of a network. As such, protocol is a somewhat simple concept, yet the interrelationship between systems and the requirements for energy and analytics make it a large and complex topic. The focus here is on relating existing data communication and BAS technology to analytics. The author believes that an understanding of these topics will assist the reader in making better everyday decisions about operations and system design. In the end, the goal here is to exchange data in the form of computer messages, and the rules for that exchange are established by the protocol. Since the exchange of messages that contain meaningful data is the goal, it is helpful to understand the concept of messaging to gain an awareness of methods used to exchange messages within computer-based systems. The discussion will then progress through a series of protocol-related topics, each of which has a bearing on data access and data resiliency.
Computer-Aided Control in Drying
Published in Alex Martynenko, Andreas Bück, Intelligent Control in Drying, 2018
A communication protocol is a system of rules that allow transmission of information from a computer to peripheral devices and vice versa. The protocol defines the rules syntax, semantics, and synchronization, and possible error recovery methods. The rules can be expressed by algorithms and data structures. Communication protocols are specific for interface, such as serial, parallel, wireless, mobile, and remote (Internet). For example, Internet protocols could include Transmission Control Protocol (TCP), Internet Control Message Protocol (ICMP), Hypertext Transfer Protocol (HTTP), Post Office Protocol (POP), Simple Mail Transfer Protocol (SMTP), File Transfer Protocol (FTP), and many others. The best-known framework is the TCP/IP protocol, which provides transmission of information from/to defined IP addresses. A good example of remote control is a sausage dryer installed in Spain but operated from Poland (Stawczyk et al., 2004). Low-level communication protocols used to exchange information between computer and instrumentation/control devices are called drivers.
Basics of Network Communications
Published in Viktor Boed, Ira Goldschmidt, Robert Hobbs, John J. McGowan, Roberto Meinrath, Frantisek Zezulka, of Facilities Automation Systems, 1999
Even before us, the end users, communications experts have struggled with similar problems and definitions. Unable to unify or define a “standard protocol,” they came up with the next best thing. They published a model for open systems interconnections (OSI) in 1977. The OSI model defines activities related to communication protocols in seven layers. The highest, the seventh layer, is interfaced to the application program, while the lowest, the 1st layer, is connected to the network media, such as twisted shielded pairs of wires or fiber optic cables. Most communication protocols in use today use either all or some of the seven layers of the OSI model (Figure 2.1).
A Generalized Numerical/Experimental Distributed Simulation Framework
Published in Journal of Earthquake Engineering, 2020
Communication protocol is a policy that two communicating modules need to follow to exchange data. It needs to be specified such that when one module sends data, the other module should receive and process the data. If both modules transmit data or wait to receive data at the same time, the communication breaks down. Current UTNP communication protocol (v. 1.0) enables both Transmission Control Protocol/Internet Protocol (TCP/IP) and User Datagram Protocol (UDP) for data exchange. It applies sequential communication, as illustrated in Fig. 3. Specifically, the server (i.e. substructure module) always waits for a connection and a command from the client (i.e. IM). Once the client is connected and a command is received, such as imposing a nodal displacement or velocity, the server runs analysis or experiment and sends the results back to the client.
Defining a Digital Twin-based Cyber-Physical Production System for autonomous manufacturing in smart shop floors
Published in International Journal of Production Research, 2019
Kai Ding, Felix T.S. Chan, Xudong Zhang, Guanghui Zhou, Fuqiang Zhang
On one hand, within the PSF, smart parts will communicate with smart resources during production in a broadcast way or a peer-to-peer way to decide optimal production sequences dynamically and react to disturbances collaboratively. The communication protocols could be DDS, MQTT and HTTP. A multi-role negotiation mechanism (Wang et al. 2016a) that clarifies the request-response and announce-bid actions can be used. With the broadcast way, smart parts will announce its next operation or process to all the smart resources, and smart resources bid for it according to their real-time capabilities and the Digital Twin simulation results. With the peer-to-peer way, one smart object whether it is a smart part or smart resource will publish a request for relevant data or information to the other certain smart object, when the latter smart object receives this message, it will gather the certain data or information in time and feed back to the former smart object for response.