Patents by Inventor Seong Wook Chang

Seong Wook Chang has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Control system using programmable logic controller
    Patent number: 6021356
    Abstract: A control system using a master programmable logic controller (PLC) which efficiently prevents the PLC system from performing an error operation caused by an abnormal state of a master PLC or a communication line error. The control system synchronizes an operating time thereof by resetting the entire remote slave units (RSU) according to the master PLC when respective power-on time points do not correspond between the master PLC and the RSUs, and selectively outputs a finally received data during a normal operation, or an emergency data predetermined by a user, when the data is not received from a master PLC.
    Type: Grant
    Filed: October 2, 1997
    Date of Patent: February 1, 2000
    Assignee: LG Industrial Systems Co., Ltd.
    Inventor: Seong Wook Chang