plc cpu modules is the control center of the programmable logic controller

plc cpu modules is the control center of the programmable logic controller. It features a programmable logic controller system according to procedures given received and stored from the plc cpu module type of user programs and data; check the power supply, memory, I / O and watchdog timer status, and can diagnose the user program syntax error. When the programmable logic controller into operation, the first of its way to scan the input device receives the status of each site and data, plc cpuand are stored in I / O image area, and then one by one to read the user program from the user program memory, after after the command execution logic required to interpret the results or arithmetic instructions fed to the I / O image area or a data register. Etc. After all the user program execution is completed, the final transfer of data I / O image area of each output state or output register to the appropriate output device, so the cycle run until it stops running...