The PLC control system design of the early, first of all, should according to the system input and output signal properties and points, and the function of the control system requirements, determine the hardware configuration of the system, such as types of CPU module and power module and need to which input / output module (Letter No. module SM), functional module (FM) and the communication processor module (CP), all module types and each type of blocks and so on. If the number of S7-300 SM, FM and CP more than 8, in addition to the central frame also need to configure the extended frame and interface module (IM). After determining the hardware composition of the system, it is required to complete the hardware configuration in STEP 7, and download the configuration information to CPU.
Hardware configuration of the task is in the step 7 generated an identical with actual hardware system and system, such as network, network in each station of the frame and module generation, and set the hardware part parameters, namely to assign a value to a parameter. All of the parameters of the module are set by the programming software, completely abolished the past used to set the parameters of the hardware DIP switch and potentiometer. Hardware configuration to determine the PLC input / output variables of the address, for the design of the user program to lay the foundation.
The parameters of the other modules in the CPU are stored in the CPU when the configuration is configured. When PLC starts, CPU automatically sends the parameters to the other modules, so after replacing the modules outside of the CPU, it is not required to re configure and download the configuration information.
PLC at startup, the STEP 7 generated in the hardware setup and the actual hardware configuration for comparison, if the two does not match, the error will be immediately reported.
Modules in the factory with the preset parameters, or as the default parameters, the general can be used for these parameters.
For already installed hardware system, with STEP 7 to establish the network in each station object, you can upload the actual configuration and parameters from the CPU through communication.
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