What is the main role of PLC communication module is

communication modules plc has a wide variety of purposes, but the main effect is the IPC host or master-slave control is established between the touch screen and downstream equipment. To choose what kind of communication module to see what you control, or what is going to a conversation. But you said the monitor is not connected thereto communication, because communication module plc is taking MODBUS or DP and industrial agreements. Monitor signal only VGA signal. So the two can not be mixed together.