Soft PLC programmable controller
Soft PLC是运行在工业PC上的一个实时多任务控制内核，它既有所有"硬"PLC的特性, 又具有自己的特性,即开放结构系统（使用C/C++和Java编程），其系统结构如图（1-1）所示。它通过软件实现数据的采集、监控等PLC功能的同时，还增加了PC机容量大、处理速度快、网络互联方便等PLC不具备的优点，是PC技术和PLC技术的结晶。
Soft PLC combines the computer’s powerful data processing and networking capabilities, friendly user interface and programming environment with the traditional PLC’s high reliability, strong anti-interference ability, flexible combination, and convenient troubleshooting. Realize the functions of PLC such as PID control, discrete control and analog control. It can use Windows9x, 2000, NT series operating systems; the signals collected by the I/O board are transmitted to the operating system of the Soft PLC software package in the industrial computer, and the application programs compiled by the user are also compiled and run in the operating system. The control quantity is sent to the actuator by the I/O board to control the controlled object.
One CPU of SOFT PLC can connect 4 boards, one board has 8 slots, a total of 32 modules, up to 1024 points, the connection method is shown in Figure (1-2). Using ring network connection, the maximum distance of optical fiber is 2K, Tealware Remote CPU can connect 15 stacks, the connection method is shown in Figure (1-3), if you use Ethernet, you can connect 254, but the use of Ethernet requires installation of drivers, cost Relatively high. The training explained in detail the usage and communication methods of SOFTPLC, such as PEAR-TO-PEAR connection method, OPC communication method and so on.
The SOFT PLC has a redundant system. It uses a dual CPU structure as shown in Figure (1-4). One is master and the other is slave. The identities of the two cannot be interchanged. The slave copies all data from the master for backup. When the system detects an abnormality in the master, it automatically realizes seamless slave replacement.