IS200BPIAG1A
IS200BPIAG1A
IS200BPIAG1A
the upper Intranet and Internet information network. Therefore, the distributed control system from this point of view is essentially a closed and special, not interoperable distributed control system and DCS cost is expensive. In this case, the users of the network control system to open and reduce the cost of urgent requirements.
4. Fieldbus control system (FCS) : FCS is born in accordance with the above trend, it uses fieldbus this open, with interoperable network will be the field controller and instrument equipment interconnection, constitute fieldbus control system, at the same time the control function is completely down to the site, reduce the installation cost and maintenance cost. Therefore, FCS is essentially an open, interoperable, completely decentralized distributed control system, which is expected to become the mainstream product of control system in the 21st century. After the emergence of computer control system, sensors, transmitters and actuators in analog
instrument system are widely used in engineering practice. The signal transmission is generally in the form of 4-20mA current signal. A transmitter or actuator needs a pair of transmission lines to transmit an analog signal in one direction. This transmission method uses many wires, the field installation and debugging of the workload is large, high investment, transmission accuracy and anti-interference ability is low, inconvenient maintenance. The main control room staff can not understand the actual situation of the field instrument, can not adjust the parameters and fault diagnosis, so at the bottom of the simulation transmitter and the actuator has become the weakest link in the computer control system, namely the development bottleneck of the so-called DCS system. Fieldbus is born in this situation.
Fieldbus technology and its characteristics
The fieldbus technology is developed in the late 80 s the scene of an advanced industrial control technology, it combines digital communication technology, computer technology, automatic control technology, network technology and intelligent instruments such as a variety of technical means, fundamentally breaks through the traditional “point to point” the limitations of analog signal or a digital analog signal control, A fully decentralized, fully digital, intelligent, two-way, interconnection, multi-variable, multi-point communication and control system. Fieldbus is a digital, bidirectional and multi-branch communication network connecting intelligent field equipment and automation system. Its foundation is intelligent instrument. The smart instruments scattered in various industrial sites are connected by a digital Fieldbus and together with controllers and monitors in
