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Fieldbus
Published in Chanchal Dey, Sunit Kumar Sen, Industrial Automation Technologies, 2020
The features associated with Foundation Fieldbus are as follows:It is a bidirectional, half duplex, digital process control and automation protocol.It supports interoperability, i.e., devices from different manufacturers (having identical specifications) can seamlessly be connected.It has a two-level architecture – a lower-level H1 operating at 31.25 kbps for the sensor-level and a higher-level H2 operating at 1 or 2.5 Mbps.Maximum distance: 1,900 m.Can be extended with repeaters. Maximum number of repeaters that can be used is four, so that maximum length that can be covered is approximately 9,500 m.Expanded view of process and devices/instruments.
Wiring, Installation, and Commissioning
Published in Sunit Kumar Sen, Fieldbus and Networking in Process Automation, 2017
Fieldbus uses a pair of wires to power the field devices and also carry the process signals to the local controller. Different types of topologies are employed to carry the bidirectional (from devices to host and vice versa) digital signals in a fieldbus system, which constitutes a local area network (LAN). Among the different fieldbuses available for different uses, Foundation Fieldbus and PROFIBUS-PA are the mostly used ones for process control purposes. They share identical networking and powering schemes, although differing significantly in communication protocol strategy.
Wiring, Installation, and Commissioning
Published in Sunit Kumar Sen, Fieldbus and Networking in Process Automation, 2014
In Foundation Fieldbus, segment length is limited to 1900 m due to attenuation along the length of the wires. Repeaters are used to increase the length of a network. A repeater refreshes the timing of a signal and boosts its amplitude to the original level at its input. A fieldbus controller chip does the above jobs. A repeater is bidirectional in nature and galvanically isolated. A maximum of four repeaters can be employed on a single network, thereby increasing the length of the network to 9500 m—thus having five segments. Schematically it is shown in Figure 23.8.
Anomaly Detection in Estimation of Load and Prediction of Load in Networked Control System Using Correlation and Regression Data Analysis
Published in IETE Journal of Research, 2023
S. M. A. K. Azad, K. Srinivasan
The Foundation Fieldbus (FF), a widespread digital and multi-drop communication protocols is used in process control industries for its advanced features like interoperability and intelligent devices connected to the network [20]. A FF network consists of four segments of 32 field devices each to configure one or more control loops. The execution and publication of each control loop's data transmitted with the speed of 31.25 Kbps in a fixed time in a data link layer of FF. The load on the segment varies with the number of devices added or removed during the maintenance of the control loop configured for the process. To configure the complete loop, components like field devices associated with other connecting equipment is compulsory in a wired network. The neglected load associated with the network equipment causes the anomaly in the estimation of the network load. Though the anomaly in load is small in large networks, it affects more in a trivial network like segments of a networked control system.
Analysis of time delays in scheduled and unscheduled communication used in process automation
Published in Automatika, 2020
S. M. A. K. Azad, K. Srinivasan
Foundation Fieldbus (FF) is one of the leading communication protocol used for remote control in industrial process automation. FF is a digital and multi-drop communication that supports interoperability where FF devices are operated remotely. Transmitter or actuator with a control unit embedded in it is called a smart device, used to control the process remotely [26]. The FF communication protocol is similar to the OSI model with four layers out of which, data link layer (DLL) plays a vital role in accessing the data. The configuration of Foundation Fieldbus devices and their medium access satisfies IEC61158 standards. FF is a communication channel between the DeviceNet and Host system (Control System) for measuring the process value of multiple control loops connected in the network for a specified time slot [27]. The typical architecture of the communication network for FF is as shown in Figure 1.