plc's cpu running program

Indicating step program memory address counter inside the PLC CPU, the program is running, the step of the counter is automatically incremented for each execution, the program from starting step (step number zero) sequentially perform the final step (typically END instruction), and then return to the starting step cycle operation. The time required for one cycle of operation is completed for each PLC is called a sweep. Different types of plc module, cycle scanning period between 1 microsecond to tens of microseconds. PLC Ladder programming logic in solving aspect, showing the advantages of fast, in microseconds, logic solver 1K less than 1 millisecond. It all inputs are processed as a switch, 16 (there are 32) is an analog. Large PLC using another CPU to perform analog operations. The calculated results to the PLC controller. The same plc IO module system, with PLC than with the DCS, the cost is lower (about can save about 40%).