If you would require to have the knowledge about the working of the PLC, it is essential that first, you have the understanding of its central processing units’ (CPU's) scanning sequence. The methodology would be basically going to be the same for all PLCs. However, as special hardware modules are going to be added into the system, additional scanning cycles would be required. Upon powering-up, the processor would be able to scan the input module as well as transfer the data contents to the input's image register or table. Data from the output image table is going to be transferred to the output module. I have learned all about the PLC, while I was learning for my certification program in here at Spoto Dumps. I must say that their expert trainers have helped me a lot and have cleared all my doubts, which build up confidence in me for appearing for the exam and clear them in a single attempt.