A/D CONVERTER AND PROGRAMMABLE CONTROLLER SYSTEM

摘要

An A/D converter which is attached to a programmable controller (PLC) and which serially converts analog values inputted from the outside into digital values is characterized in that the A/D converter is provided with shared memory readable and accessible from a CPU unit for controlling the global PLC provided with a log storage area having a ring buffer configuration for serially logging the digital values and a parameter storage area for storing a head pointer which is a parameter indicating the storage position of the next log data, and a logging execution section for writing the digital values to an address indicated by the head pointer of the log storage area as the log data and updating the head pointer.