APPARATUS AND METHOD FOR DETECTING LINE DISCONNECTION OF ANALOG INPUT MODULE

摘要

An apparatus and a method for detecting line disconnection of an analog input module are provided to determine an abnormal state of an input value of an analog input module by using PLC(Programmable Logic Controller) software without using a line disconnection circuit. An input unit(110) receives a voltage or a current input value inputted through an external sensor as an analog input value. An amplifier unit(120) amplifies the analog input value according to an input range. An A/D conversion unit(130) converts the received analog input value to a digital value. A processor unit(150) has minimum reference value information according to a range of the digital value. The processor unit sense errors due to line disconnection when the digital value is less than a minimum reference value. An insulation unit(140) is installed between the A/D conversion unit and the processor unit in order to insulate an analog processor unit and a digital processor unit.