A FIRMWARE DOWNLOAD METHOD FOR A EXPANSION MODULE IN A PROGRAMMABLE LOGIC CONTROLLER

摘要

A method of downloading firmware to an extension module of a programmable logic controller is provided to download firmware to the extension module without using a physical component such as an RS-232C serial communication connector and an RS-232C serial communication transceiver. Firmware included in a programmable logic controller is downloaded to a main unit(2) of the programmable logic controller by using serial communication. A CMOS(Complementary Metal Oxide Semiconductor) level signal communication connector(21) of the main unit of the programmable logic controller is connected to a CMOS level signal communication connector(35) of an extension module(3) of the programmable logic controller to download the firmware from the main unit of the programmable logic controller to the extension module of the programmable logic controller.