What properties, advantages and special features does the global data communication offer?
Description: Global data communication permits cyclic data communication between SIMATIC S7 CPUs via the MPI interface. Data communication is cyclic during updating of the process output and input images. In addition to cyclic data transfer, it is also possible to have event-controlled data transfer in the S7-400 CPU via prepared function blocks. For this, function blocks are called in the S7 program for sending and receiving the data. The data to be transferred is defined statically in the program and can be transferred consistently in different global data rings, i.e. defined groups of nodes that exchange global data with each other. The data can only be transferred to modules that have been parameterized in the same STEP 7 project and that use either the same communications bus (K bus) on the backplane bus or the MPI bus. Global data communication and MPI are located as follows in the ISO-OSI reference model. Fig.
