六、PLC最新发展状态及趋势
现代PLC的发展有两个主要趋势：其一是向体积更小、速度更快、功能更强和价格更低的微小型方面发展；其二是向大型网络化、高可靠性、好的兼容性和多功能方面发展。
（1）大型网络化主要是朝DCS方向发展，使其具有DCS系统的一些功能。网络化和通信能力强是PLC发展的一个重要方面，向下可将多个PLC、I/O框架相连；向上与工业计算机、以太网、MAP网等相连构成整个工厂的自动化控制系统。
（2）多功能随着自调整、步进电机控制、位置控制、伺服控制等模块的出现，使PLC控制领域更加宽广。
system, thereby reducing
cost and time investment in establishing data communication and interactive access.
And ensure the consistency of data throughout the system.
●Provide system-wide unified inspection of user applications, overriding
from process control stations, operator stations to intelligent field devices, including
Including the integrity and consistency check of the user program.
●The programming language strictly complies with the international standard of IEC61131-3, and has
There are high-performance graphics editing functions:
– Function Block Diagram (FBD)
-Ladder Diagram (LD)
– Instruction List (IL)
– Sequence Control Chart (SFC)
. Structured Text (ST)
●Extensive function block library, user-defined function blocks can also be added
Added to it, the macro library and graphic symbols can be customized for the user.
Blocks can create graphics and operator panels.
●Any standard can be integrated by means of GSD file import
PROFIBUS-DP and PA devices, and through user-defined pairing
dialog box to design the configuration window for these devices.
●Profibus field controller can be integrated through FDT/DTM technology
line equipment
system structure
The Freelance 800F process control system is divided into operator levels
and
