×

Method and apparatus for an active standby control system on a network

  • US 7,032,029 B1
  • Filed: 07/07/2000
  • Issued: 04/18/2006
  • Est. Priority Date: 07/07/2000
  • Status: Expired due to Term
First Claim
Patent Images

1. A method of providing an active standby control system comprising the step of:

  • providing a first and a second programmable logic controller, each programmable logic controller having an operating state, an I/O scanner having a connection to a remote I/O head, and a hot standby nodule, wherein each programmable logic controller'"'"'s hot standby module is operably connected together, operably connecting each programmable logic controller to a network;

    assigning a network address identifier to each programmable logic controller, wherein the network address identifier is a Media Access Control address;

    placing the first programmable logic controller in primary mode and the second programmable logic controller in secondary mode;

    sensing the operating state of each programmable logic controller;

    exchanging the network address identifiers between the first programmable logic controller and the second programmable logic controller upon detection of a failure in the first programmable logic controller; and

    resetting the connection between the I/O scanner and the remote I/O head in the first primary programmable logic controller prior to exchanging the network address identifiers.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×