Devices, systems and methods for communicating with a PLC

• US 7,792,043 B2
• Filed: 08/08/2007
• Issued: 09/07/2010
• Est. Priority Date: 08/08/2006
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens Industry Incorporated (Siemens AG)
• Inventors: Boggs, Mark Steven, McNutt, Alan D., Fulton, Temple L.
• Primary Examiner(s): Ngo; Ricky
• Assistant Examiner(s): Mui; Gary
• Application Number:
  US11/890,872
• Publication Number:
  US 20080125885A1
• Time in Patent Office: 1,126 Days
• Field of Search: 370/216, 370242-245, 370/389, 370464-467, 370470-479, 714/100, 714/1, 714/2, 714 48- 57, 709224-226
• US Class Current: 370/242
• CPC Class Codes: G05B 19/054 Input/output
• CPC Class Codes: G05B 2219/1109 Expansion, extension of I-O
• CPC Class Codes: G05B 2219/1113 Address setting
• CPC Class Codes: G05B 2219/15072 Modules in daisy chain, connected by parallel cable
• CPC Class Codes: H04L 1/00 Arrangements for detecting or preventing errors in the information received correcting synchronisation H04L7/00
• CPC Class Codes: H04L 25/4908 using mBnB codes

Abstract

Certain exemplary embodiments can comprise a system, which can comprise a module communicatively coupled to a programmable logic controller (PLC). The module can comprise a transmission circuit and/or a receiving circuit. The module can be adapted to communicate with the PLC via 8B/10B encoded frames. A frame of the 8B/10B encoded frames can comprise a plurality of ordered fields.

Claims

1. A method comprising:

transmitting a first message from a programmable logic controller (PLC) toward a module;

receiving a second message at said PLC from said module, responsive to an automatic determination of an error associated with said first message transmitted by said PLC toward said module, said second message transmitted via a first 8B/10B encoded frame;

including in said second message an error classification and an error code;

providing one or more of automatic interpretation, reporting, and corrective action by said PLC in response to said error classifications;

including in said first 8B/10B encoded frame a message type field of a size that corresponds to eight bits, a value stored in said message type field indicative of content of a data field of said frame, said message type field following a sequence of fields comprised by said frame; and

including in said sequence of fields a preamble field, a start-of-frame field, a destination address field, a length field, and a source address field.

2. The method of claim 1, wherein, said error classification and said error code comprises:

providing information regarding said module, a receipt by said module of said first message, an ability of said module to understand said first message, or an ability of said module to utilize said first message.

3. The method of claim 1, wherein said first 8B/10B encoded frame comprises:

providing a device class field to receive a value indicative of a device class of said module.

4. The method of claim 1, wherein said first 8B/10B encoded frame comprises:

providing a device type field to receive a value indicative of a device type of said module.

5. The method of claim 1, wherein said first 8B/10B encoded frame comprises:

providing a device status field to receive a value indicative of a status of said module.

6. The method of claim 1, wherein said error classification field contains a value indicative of a non-fatal device error.

7. The method of claim 1, wherein said error code field contains a value indicative that a message type of said first message is an unsupported message type for said module.

8. The method of claim 1, wherein said error code field that contains a value indicative that said first message attempted to assign an invalid address for an address of said module.

9. The method of claim 1, wherein said error code field contains a value indicative that said first message attempted to enable communications with a communicatively coupled second module, and such communication had been previously enabled.

10. The method of claim 1, wherein said error code field contains a value indicative that an incorrect input/output count was referenced by said transmitted first message.

11. The method of claim 1, wherein said error code field contains a value indicative that an invalid component number was referenced by said transmitted first message.

12. The method of claim 1, wherein said error code field contains a value indicative that a write operation to a memory comprised by said module failed.

13. The method of claim 1, wherein said error code field contains a value indicative that a component update operation is in progress at said module.

14. The method of claim 1, wherein said error code field contains a value indicative of an invalid message format in said transmitted first message.

15. The method of claim 1, wherein said error code field contains a value indicative of invalid downloaded content.

16. The method of claim 1, wherein said error code field contains a value indicative of an invalid discovered component.

17. A non-transitory machine-readable medium comprising machine instructions for implementing activities comprising:

transmitting a first message from a programmable logic controller (PLC) toward a module;

receiving a second message at said PLC from said module, responsive to an automatic determination of an error associated with a first message transmitted by said PLC toward said module;

providing said second message transmitted via a first 8B/10B encoded frame;

including in said second message an error classification and an error code;

providing one or more of automatic interpretation, reporting, and corrective action by said PLC in response to said error classifications;

said error classification and said error code further comprising;

providing information regarding said module, a receipt by said module of said first message, an ability of said module to understand said first message, or an ability of said module to utilize said first message;

including in said first 8B/10B encoded frame a message type field of a size that corresponds to eight bits, a value stored in said message type field indicative of content of a data field of said frame, said message type field following a first ordered sequence of fields comprised by said frame;

including in said first ordered sequence of fields;

a preamble field, a start-of-frame field, a destination address field of a size that corresponds to eight bits, a length field, and a source address field of a size that corresponds to eight bits, said message type field followed by a second ordered sequence of fields comprised by said frame; and

including in said second ordered sequence;

a data field, a cyclic redundancy check field of a size that corresponds to 32 bits, and an end of frame field.

18. A system comprising:

a circuit adapted to;

receive a second message at a programmable logic controller (PLC) from a module, responsive to an automatic determination of an error associated with a first message transmitted by said PLC toward said module, said second message transmitted via a first 8B/10B encoded frame, said second message comprising an error classification and an error code, said error classification and said error code provide information regarding said module, a receipt by said module of said first message, an ability of said module to understand said first message, or an ability of said module to utilize said first message, said first 8B/10B encoded frame comprising an eight bit a single symbol message type field, a value stored in said message type field indicative of content of a data field of said frame, said message type field following a sequence of fields comprised by said frame, said sequence of fields comprising a preamble field, a start-of-frame field, a destination address field a length field, and a source address field; and

at least one of interpret, report, and take corrective action at by said PLC, responsive to said error classification.