Devices, systems, and methods regarding a PLC

• US 20080133789A1
• Filed: 08/08/2007
• Published: 06/05/2008
• Est. Priority Date: 08/08/2006
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Boggs, Mark Steven, McNutt, Alan D., Fulton, Temple L.
• Granted Patent: US 8,417,847 B2
• Time in Patent Office: Days
• US Class Current: 710/30
• 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 system comprising:

a first module of a first chain of modules, each adjacent pair of said first chain of modules communicatively coupled in series, said first module communicatively coupled to a programmable logic controller (PLC), said first module comprising a transmission circuit and a reception circuit, said first module adapted to communicate with said PLC via 8B/10B encoded frames, a frame of said 8B/10B encoded frames comprising 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 each of said frames, said message type field following an ordered sequence of fields comprised by said frame, said ordered 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 system of claim 1, further comprising:

a second chain of modules, each adjacent pair of said second chain of modules communicatively coupled in series.

3. The system of claim 1, further comprising:

said PLC.

4. The system of claim 1, wherein said 8B/10B encoded frames comprise a data field.

5. The system of claim 1, wherein said 8B/10B encoded frames comprise a cyclic redundancy check field.

6. The system of claim 1, wherein said 8B/10B encoded frames comprise a cyclic redundancy check field of a size that corresponds to 32 bits.

7. The system of claim 1, wherein said 8B/10B encoded frames comprise one or more end-of-frame characters.

8. The system of claim 1, wherein said 8B/10B encoded frames are comprised by a serially transmitted message.

9. The system of claim 1, wherein Input/Output modules and communications modules are located on different chains of modules, said Input/Output modules adapted to communicate with said PLC in hard real-time.

10. The system of claim 1, wherein said first chain comprises only Input/Output modules or only communications modules.

11. The system of claim 1, wherein said first chain of modules comprises an Input/Output module adapted to communicate with said PLC in hard real-time.

12. The system of claim 1, wherein said destination address field is of a size that corresponds to eight bits.

13. The system of claim 1, wherein said destination address field is adapted to receive a value that is indicative of an un-configured address used during address assignment of said first chain of modules.

14. The system of claim 1, wherein said destination address field is adapted to receive a value that is indicative of broadcast address that is used to broadcast a message to all of said first chain of modules.

15. The system of claim 1, wherein said first module is implemented via an ASIC controlled by machine instructions.

16. The system of claim 1, wherein said first module is implemented via an FPGA controlled by machine instructions.

17. A data structure encoded on a machine-readable medium, said data structure adapted for transferring data between a module and a programmable logic controller (PLC), said data structure comprising:

an 8B/10B encoded frame adapted for communication between said module and said programmable logic controller (PLC), said 8B/10B encoded frame comprising 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 an ordered sequence of fields comprised by said frame, said ordered sequence of fields a preamble field, a start-of-frame field, a destination address field, a length field, and a source address field.

18. A method comprising:

encoding a message via 8B/10B encoded frames, said message adapted for communication in hard real-time between an Input/Output module and a programmable logic controller (PLC), said Input/Output module one of a first chain of Input/Output modules communicatively coupled in series to said PLC, said Input/Output module comprising a transmission circuit and a receiving circuit, said PLC communicatively coupled in series to a second chain of communications modules, at least one of said second chain of communications modules adapted to be communicatively coupled to an information device, said 8B/10B encoded frames comprising 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 a given frame, said message type field following a first ordered sequence of fields comprised by each of said frames, 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 each frame, said second ordered sequence comprising a data field, a cyclic redundancy check field of a size that corresponds to 32 bits, and an end of frame field.

19. A machine-readable medium comprising machine instructions for activities comprising:

encoding a message via 8B/10B encoded frames, said message adapted for communication between a module and a programmable logic controller (PLC), said 8B/10B encoded frames comprising 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 an ordered sequence of fields comprised by each of frames, said ordered sequence of fields a preamble field, a start-of-frame field, a destination address field, a length field, and a source address field.