System and method for accessing PLC data on demand

• US 20050203648A1
• Filed: 02/15/2005
• Published: 09/15/2005
• Est. Priority Date: 03/15/2004
• Status: Active Grant

• Current Assignee: Siemens Industry Incorporated (Siemens AG)
• Original Assignee: Siemens Industry Incorporated (Siemens AG)
• Inventors: Martin, David
• Granted Patent: US 8,738,159 B2
• Time in Patent Office: Days
• US Class Current: 700/87
• CPC Class Codes: G05B 15/02 electric
• CPC Class Codes: G05B 19/05 Programmable logic controllers, e.g. simulating logic interconnections of signals according to ladder diagrams or function charts
• CPC Class Codes: G05B 19/052 Linking several PLC's
• CPC Class Codes: G05B 19/056 Programming the PLC
• CPC Class Codes: G05B 19/408 characterised by data handling or data format, e.g. reading, buffering or conversion of data
• CPC Class Codes: G05B 19/409 characterised by using manual data input [MDI] or by using control panel, e.g. controlling functions with the panel; characterised by control panel details or by setting parameters G05B19/408, G05B19/4093 take precedence
• CPC Class Codes: G05B 2219/1205 Memory access for different processors, memory arbitration, mailbox
• CPC Class Codes: G05B 2219/1208 Communication, exchange of control, I-O data between different plc,
• CPC Class Codes: G05B 2219/2222 Use of priority levels for gaining access to resources
• CPC Class Codes: G06F 11/2074 Asynchronous techniques
• CPC Class Codes: G06F 16/284 Relational databases
• CPC Class Codes: G06F 21/31 User authentication
• CPC Class Codes: G06F 21/78 to assure secure storage of data address-based protection against unauthorised use of memory G06F12/14; record carriers for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: G06F 9/547 Remote procedure calls [RPC]; Web services
• CPC Class Codes: H04L 63/083 using passwords cryptographic mechanisms or cryptographic arrangements for entity authentication using a predetermined code H04L9/3226
• CPC Class Codes: H04L 9/3226 using a predetermined code, e.g. password, passphrase or PIN network architectures or network communication protocols for supporting authentication of entities using passwords in a packet data network H04L63/083
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99937 Sorting

Abstract

A system for providing programmable logic data on demand includes a portion for receiving a plurality of data requests at the programmable logic controller and a portion for processing the plurality of data requests asynchronously. An interface enables asynchronous processing to enhance and extend capabilities of the programmable logic controller.

Claims

1. A method for providing programmable logic controller data on demand, the method comprising the steps of:

loading an access code from an external application for pass through access to a memory area of a programmable logic controller;

receiving a function call at the programmable logic controller from the external application; and

accessing a plurality of memory locations on demand in the area of the programmable logic controller in response to the function call.

2. The method as in claim 1, wherein the function call is one of a read call, a write call, a cyclic data request or combinations thereof.

3. The method of claim 2, further comprising the steps of:

receiving a call to create the cyclic data request; and

processing the cyclic data request.

4. The method of claim 2, further comprising the steps of:

receiving a call to terminate processing of the cyclic data request; and

terminating the processing.

5. The method as in claim 2, further comprising the step of receiving a call to delete a cyclic read of the plurality of memory locations.

6. The method as in claim 1, further comprising the step of returning data stored at the memory area to the external application in response to the function call.

7. A method for providing programmable logic controller data on demand, the method comprising the steps of:

receiving a plurality of data requests at a programmable logic controller; and

processing the plurality of data requests asynchronously.

8. The method as in claim 7, further comprising the step of providing means for direct access to at least one memory location of the programmable logic controller.

9. A system for providing programmable logic data on demand, the system comprising:

a programmable logic controller having at least one memory area;

means for receiving a call on demand from at least one external entity; and

means for directly accessing the memory area.

10. The system as in claim 9, wherein the means for receiving is a portion of an interface defined in a dynamic linked library.

11. The system as in claim 10, wherein the call is one of a read call, a write call, a plurality of cyclic reads or combinations thereof.

12. The system as in claim 11, wherein the external entity is configured to create, start, stop, or delete the cyclic reads.

13. The system as in claim 9, wherein the means for directly accessing the memory area is defined in a segment of the external entity downloadable by the means for receiving.

14. A system for providing programmable logic data on demand, the system comprising:

a first portion for receiving a plurality of data requests at a programmable logic controller; and

a second portion for processing the plurality of data requests asynchronously, wherein an interface enables the asynchronous processing.

15. The system as in claim 14, wherein the first portion is a dynamic linked library associated with the programmable logic controller.

16. The system as in claim 14, wherein the second portion is selected from the group consisting of a dynamic linked library associated with an application, a memory area defined in the programmable logic controller, and combinations thereof.

17. The system as in claim 14, wherein the interface establishes a pass through portal from the external application to a memory area of the programmable logic controller, the pass through portal configured for loading into a dynamic linked library associated with the programmable logic controller.