S7' s basic storage area in M area can be used for bit logic, integer, double integer, and real number MD20 = MW20+MW22 = M20.0 ~ 7+M 21.0 ~ 7+M22.0 ~ 7+M23.0. ..
Control proportion:
It can be divided into mainframe, medium-sized computer and minicomputer.
Minicomputer: The control point of minicomputer is generally less than 256 points, which is suitable for single machine control or small system control.
Siemens minicomputer has S7-200: the processing speed is 0.8 ~1.2 ms; Memory 2 k; The number is 248 points; Analog 35 channels.
Medium-sized machine: The control point of medium-sized machine is generally less than 2048 points, which can be used for direct control of equipment and monitoring of multiple lower-level programmable controllers. Suitable for medium or large control systems.
Siemens medium-sized machine has S7-300: the processing speed is 0.8 ~1.2 ms; Memory 2 k; Digital quantity 1024 points; Analog 128 channel; Network PROFIBUS；; Industrial Ethernet; MPI .