METHOD FOR CHANGING SPEED OF COMMUNICATION BETWEEN PLC AND COMPUTER

摘要

PURPOSE: A method for changing a speed of communication between a PLC(programming logic controller) and a computer is provided to increase the operation efficiency of a CPU by enabling the CPU of a PLC to simply set a communication speed as a determined speed and to wait an external communication request. CONSTITUTION: A power supply is provided to a computer to which a PADT(Programming and Debugging Tool) is mounted and a PLC(Programmable Logic Controller)(1). A CPU of the PLC waits an external communication request in setting a communication speed as 9600bps(2). The computer transmits a signal for making the PLC a request for communication in order to communicate with the PLC(3). The PLC receives the communication request signal from the computer and transmits a response signal(4). The computer transmits information to the PLC in order to change a new communication speed into an initial communication speed(5). The communication speed of the computer is changed into the new communication speed desired(6). The PLC receives information on the new communication speed and changes the communication speed(7). The PLC transmits the response signal to the computer at the new speed(8). In case that the communication is cut off, the communication is tried at the initial communication speed(9).