PLC I/O MODULE AND METHOD DETECTING DATA ERROR FROM INPUTTED DIGITAL DATA

摘要

PURPOSE: A PLC(Programmable Logic Controller) I/O(Input/Output) module and a method detecting a data error are provided to secure reliability and stability through prevention of the data error by converting digital data into analog data and outputting the analog data only if the digital data inputted from the outside is identical with the digital data output through a Daisy chain. CONSTITUTION: An input part(50) outputs the digital data by a control signal received from the outside. A DAC(Digital Analog Converter) part(60) comprises shift registers(60a,60c) to output the digital data for error detection of the digital output from the input part, and a DAC(Digital Analog Converter)(60b) converting the digital data output from the input part into the analog data and outputting the analog data to an amplifying part(30). A data comparing part(70) compares the digital data output from the DAC part with the digital data output from the input part, and outputs the control signal to the input part or outputs the digital data to the DAC part.