Programmable logic controller provided with communication functions in a client-server architecture

• US 20010014833A1
• Filed: 01/25/2001
• Published: 08/16/2001
• Est. Priority Date: 01/26/2000
• Status: Active Grant

• Current Assignee: Schneider Automation (Schneider Electric SE)
• Original Assignee: Schneider Electric Industries Sa (Schneider Electric SE)
• Inventors: Brault, Gilbert
• Granted Patent: US 6,721,607 B2
• Time in Patent Office: Days
• US Class Current: 700/18
• CPC Class Codes: G05B 19/05 Programmable logic controllers, e.g. simulating logic interconnections of signals according to ladder diagrams or function charts

Abstract

This invention relates to a programmable logic controller (PLC) provided with communication functions in a client-server architecture and a private operating system that does not support the TCP/IP protocol but is adapted to automation programs and is equipped firstly with at least one intelligent module (MM, UC) in which an HTTP server is installed, and also a communication module (MC) that can be connected to remote equipment (C) through a bus, characterized by the fact that the intelligent module (MM, UC) is provided with an application programming interface (TCP API) that makes it possible to use connection and communication (TCP) functions of the TCP/IP type of communication module (MC), from a remote location.

Claims

1. Programmable logic controller (PLC) provided with a private operating system that does not support the TCP/IP protocol but is adapted to automation programs and is equipped firstly with at least one intelligent module (MM, UC) in which an HTTP server is installed, and also a communication module (MC) that can be connected to remote equipment (C) through a bus, characterized by the fact that the intelligent module (MM, UC) is provided with an application programming interface (TCP API) that makes it possible to use connection and communication (TCP) functions of the TCP/IP type of communication module (MC), from a remote location.

2. Logic controller according to

claim 1

, characterized by the fact that the communication module (MC) comprises a Server delegation service that an application in a module MM can use to delegate opening and management of a server connection to the TCP/IP network to the said module MC, a client delegation service that an application in a module MM can use to delegate the MC module opening and management of a client connection on the TCP/IP network, a Multicast delegation service enabling an application of an MM module to delegate opening and management of a Multicast connection on the TCP/IP network to module MC, and a transcoding and routing service that can encode requests originating from the previous services using one of the protocols supported by the private communication bus, in order to route them towards intelligent modules and to decode requests from intelligent modules and route them to the delegation services.

3. Logic controller according to

claim 1

or

2

, characterized by the fact that the application programming interface (TCP API) comprises functions that behave in a manner similar to the functions with the same names in the libc library of the gnu c compiler but with additional arguments to encode information so that it can be transported on the private communication bus (BP) and can be interpreted by delegated services of the communication module (MC) and switch messages from the said interface (TCP API) on the private communication bus (BP).

4. Logic controller according to

claim 1

,

2

or 3, characterized by the fact that the first call to a function sends a request to the delegated service of the communication module (MC) and initializes a status block transferred as a parameter, in order to guarantee asynchronism between the application in the communication module (MM) and delegated services in the communication module (MC), and by the fact that subsequent calls with the same status block are used to retrieve function return parameters, a message being sent to the intelligent module (MM) when a function is terminated in the module (MC).