DUAL ETHERNET STACK FOR MAXIMUM SPEED ACCESS TO A PLC

摘要

A control system includes an Internet web interface to a network of at least one programmable logic control system running an application program for controlling output devices in response to status of input devices. The Web interface runs Web pages from an Ethernet board coupled directly to the PLC back plane and includes an HTTP protocol interpreter, a PLC back plane drive r, a TCP/IP stack, and an Ethernet board kernel. The Web inteface provides acce ss to the PLC back plane by a user at a remote location through the Internet. T he interface translates the industry standard Ethernet, TCP/IP and HTTP protoco ls used on the Internet into data recognizable to the PLC. Using this interface , the user can retrieve all pertinent data regarding the operation of the programmable logic controller system.