Client - server communication system uses file groups in XML format which are revealed according to file type

摘要

The system provides communication between a programmable computer (PLC) provided with an HTTP server, and a client machine (C) via a network (B). Within the central unit (UC) of the computer there is a device for adding file groups (M1, M2..) in XML format, within which are grouped the signal elements which are intended to observe or control the automated process. A further device adds or suppresses elements of these files according to file type, whilst another element reads or writes to these files in response to requests send to the HTTP server. Each of the signal elements is in XML format, and comprises the definition which indicates the type of signal and its binary value.