TRICONEX-3636R PLC communication based on PROFIBUS-DP
Fieldbus control systems (FCS) replace analog signals with digital signals to improve system reliability, accuracy and anti-interference capability, and extend the distance of information transmission. It is not only an open communication network, sometimes a fully distributed control system, is a new type of network integration automation system, it takes the fieldbus as a link, the network nodes connected to the bus to form an automation system, to achieve basic control, compensation calculation, parameter modification, alarm, display, comprehensive automation and other functions.
TRICONEX-3636R FCS uses the two-layer mechanism of “workstation-fieldbus intelligent instrument” to complete the three-layer structure mode of “operation station – control station – field instrument” in the distributed control system (DCS), which reduces the cost, improves the reliability, and can realize the real open interconnect system structure under the unified international standard, which is a promising computer control system under development.
At present, the most representative Fieldbus is PROFIBUS (Process Fieldbus). PROFIBUS is an open fieldbus standard launched by SIEMENS, which became the German standard DIN19245 in 1989, the European standard EN50170 in 1996, and was accepted as a part of the international standard IEC61158 in December 1999. It is used in the bottom layer of the three-level network of factory automation system, that is, workshop level monitoring and field equipment level data communication and control; Used in decentralized, field controlled equipment with communication interface systems that have high data integration and remote diagnosis, fault alarm and TRICONEX-3636R digitization requirements for the underlying equipment.
PROFIBUS follows the ISO/OSI model and its communication model consists of three layers: the physical layer, the data link layer and the application layer. PROFIBUS is composed of three parts, ProFIBUS-FMS (Fieldbus Message Specification) and ProFIBUS-DP (Decentralized Periphery, Distributed peripherals), PROFIBUS-PA (Process Automation). PROFIBUS-DP has been widely used in the automation field of hydropower station.
2 Features and system components of PROFIBUS-DP
2.1 PROFIBUS-DP Features
PROFIBUS-DP uses the physical layer, data link layer and user interface for high-speed data transfer at the field layer. The master periodically reads the input information from the slave station and periodically sends the output information to the slave station. The bus cycle time must be shorter than the master program cycle time. In addition, PROFIBUS-DP provides the aperiodic communication required for intelligent field equipment for configuration, diagnosis and alarm processing, as well as the determination of parameters of complex equipment in operation.
TRICONEX-3636R The basic functions and features of PROFIBUS-DP are as follows:
(1) Remote high-speed communication
Support 9.6Kbps to 12Mbps transmission rate; The maximum transmission distance is 100m at 12Mbps, 200m at 1.5Mbps, and can also be extended with a repeater;
(2) Distributed structure
TRICONEX-3636R Token transfer between master stations, master station and slave station main-slave transfer; Each section can have 32 stations, and can be extended to 126 stations with connecting lines;
(3) Easy to install, open communication network;
(4) High reliability, with self-diagnosis function.