PLC typical boot process

input Refreshrerun user programsand then output refreshthen enter refresh then run user programs and then output the brush never stop the cycle repeated manner. With PLC control is clearly possible. Because: With input refresh, enter information analog input plc can be obtained by monitoring the input circuit stores the PLC input mapping area; by running the user program, the output mapping area will get the information transformed; then by the output refresh, the output latch will reflect the state of the output mapping area, and generates a corresponding output via the output circuit. Also, because this process is never-ending cycle of repeatedly plc ethernet module engaged in ground, so the output always reflects the change in input. The only response time, a slight lag. Of course, this lag should not be too large, otherwise, control achieved not so timely, it lost control of meaning. To this end, the working speed of the PLC to be fast. Fast instruction execution time is short, is the basis for control of the PLC. In fact, its speed is very fast, execute a command, and more a few microseconds, tens of microseconds, only a few tenths less, or 0.0 microseconds. And this rate still increasing in.