S7-300 has a variety of different communication interfaces, notably the following:
1) multiple communications processors to connect to the as-I interface, PROFIBUS and Ethernet bus systems.
2) serial communications processor is used to connect to a point-to-point communication system.
3) multi-point interface (MPI) integrated in the CPU, for connected programmer, PLC HMI systems and other automated control systems such as SIMATIC S7/M7/C7.
Peep _ in the control Department, through a communication interface through the communications function has the following types:
1. Process communication via Profibus-DP
S7-300 communication processors, or integrated on the CPU PROFIBUS-DP connected to the PROFIBUS-DP network. CPU with PROFIBUS-DP master/slave interface can achieve high-speed, user-friendly distributed Automation configuration. From the user point of view, as set through the PROFIBUS-DP distributed I/O I/O, have the same configuration, the address, and programming.
2. Through the AS-I process communication
As-I interface bus, S7-300 CP342-2 communication processor connected field devices.
3. Data communication
S7-300 has a useful global data communications network for data communication exchange of packets between the CPU cycles. Through global data communication services, networked CPU can periodically exchange data with each other. In addition, you can use the communication functions for data communications, network communication function block other sites for event–driven communications. For networking, you can use the MPI, PROFIBUS or industrial Ethernet data communication. Comparison with the global data, communication connection must be established for the communications function. Here are several typical data communication.
Data communication of communication CP (point-to-point links): CP340/CP341 communication module can be used to establish a point-to-point link in 3 communication interface based on 20mA (TTY), RS-232C, RS-422/RS-485 and other communication protocols can be used. You can connect devices such as: series PLC S7 and S5 series PLC and third–party systems, printers, bar code readers and other equipment.
Through the interface (MPI) communication: multi-point interface (MPI) communication integrated in the S7-300 on the CPU, it can be used for simple networking. MPI can simultaneously connect several SETP7 for programmer/PLC, human-machine interface (HMI). The CPU can use global data networking (GD) service that periodically exchange data with each other, S7-300 CPU up to 4 22B packets can be exchanged, but can have up to 16 CPU in data exchange. Global data communication only via the MPI interface. CPU MPI is directly connected to the S7-300 k–bus, can be used for programming from the k–bus interface through MPI, FM/CP modules are directly addressed.
Data communication via CP (PROFIBUS or industrial Ethernet): via CP342/343 communications processor SIMATIC S7-300 connected with the industrial Ethernet and PROFIBUS bus system. Connected devices, such as SIMATIC S7-300, SIMATIC S7-400, programmer, personal computer (PC) non-Siemens devices, drive controllers, and so on.