IS200VAICH1C
IS200VAICH1C
IS200VAICH1C
international standard and draft, together with its technical advantages, so it is very promising to become a major international standard in the future.
The FF bus provides two physical layer standards, Hl and H2. Hl is a low-speed bus for process control, with a transmission rate of 31.25Kbps and a transmission distance of 200m, 450m, 1200m and 1900m (which can be extended with repeater). It can be powered by bus and support essential safety equipment and non-essential safety bus equipment. H2 is a high-speed bus with a transmission rate of 1Mbps (the transmission distance is 750m) or 2.5bps (the transmission distance is 500m). The number of nodes in each segment of H1 and H2 can reach 32, and the number can reach 240 after using repeater. Hl and H2 can be interconnected through a bridge. FF’s outstanding features are interoperability, improved process data, earlier predictive maintenance, and reliable security.
3.2 Process Fieldbus Profibus
Profibus, proposed and strongly advocated by Siemens, has become the German national standard DIN19245 and the European standard EN50170. As an open and independent bus standard, ProFIBUS serves as a communication network in machinery manufacturing, industrial process control and intelligent buildings. Profibus consists of PROFIBUS-PA, PROFIBUS-DP, and PROFIBUS-FMS series. Profibus-PA (Process Automation) is used for low speed data transmission of process automation, its basic characteristics are the same as FF H1 bus, can provide bus power supply and essential security, and is supported by ASIC and software. Profibus-DP is compatible with Profibus-PA and has the same basic characteristics as FF’s H2 bus, which can realize high-speed transmission. It is suitable for high-speed data transmission between scattered external equipment and automatic control equipment, and is used to connect Profibus-PA and processing automation. Profibus-FMS IS suitable for medium speed data transmission in general automation, mainly used in sensors, actuators, electrical drives, PLC, textile and building automation, etc. The latter two series adopt RS485 communication standards, with transmission rates ranging from 9.6kbps to 12Mbps, and transmission distances ranging from 1200M to l00m (depending on the transmission rate). The basic modes of media access control are token mode between master stations and master/slave mode between MASTER and slave stations, as well as hybrid mode combining the two modes. Profibus is a mature bus, which is widely used in engineering.
4. The influence of FCS on computer control system
Traditional computer control system generally uses DCS structure. In DCS, A POINT-TO-POINT CONNECTION IS REQUIRED FOR FIELD SIGNALS, AND THE I/O TERMINALS ARE PLACED IN THE CONTROL CABINET WITH THE PLC OR AUTOMATED METER, RATHER THAN IN THE FIELD. This requires laying a large number of signal transmission cables, wiring complex, both cost material and time consuming, signal attenuation and easy to be