Can any body tell me how to connect both analog & Digital I/P & O/P's modules through PLC. If you have any diagram plz attach it... Actually i want to know from the basic , that when signal is given to PLC for any action to be performed through HMI... how does the signal goes through the plc then the relay & then to the field . if any signal responds to plc how the signal comes bac fromthe field and displays on HMI screen to the user through the plc. Plz help me on this.... Thanking you