Devices, systems, and methods for assigning a PLC module address

• US 20080091931A1
• Filed: 08/08/2007
• Published: 04/17/2008
• Est. Priority Date: 08/08/2006
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: McNutt, Alan, Fulton, Temple, Boggs, Mark
• Granted Patent: US 8,321,653 B2
• Time in Patent Office: Days
• US Class Current: 713/1
• 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:

sending a first message from a programmable logic controller (PLC) to a module, said first message transmitted via a first 8B/10B encoded frame that comprises a destination address corresponding to an eight bit default module address of said module, said first message adapted to set a module address of said module to an assigned address value and transmit a reply message via a second 8B/10B encoded frame that comprises a source address that confirms said assigned address value has been assigned to said module by said first message, said first 8B/10B encoded frame 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 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.

2. The method of claim 1, further comprising:

receiving said first message.

3. The method of claim 1, further comprising:

responsive to a failure to receive said reply message, sending a second message via a third 8B/10B encoded frame to said module, said second message adapted to set said module address to said default eight bit module address.

4. The method of claim 1, further comprising:

responsive to a failure to receive said reply message, sending a second message via a third 8B/10B encoded frame to said module, said second message adapted to set said module address to said default module address; and

responsive to said second message, receiving a response message via a fourth 8B/10B encoded frame, said response message adapted to confirm that said module address has been reset to said default eight bit module address.

5. The method of claim 1, further comprising:

sending a second message via a third 8B/10B encoded frame to said module, said second message adapted to cause said module to enable communications with a communicatively coupled second module and to send a confirming message acknowledging receipt and action in response to said second message.

6. The method of claim 1, further comprising:

sending a second message via a third 8B/10B encoded frame to said module, said second message adapted to cause said module to enable communications with a communicatively coupled second module and to send a confirming message acknowledging receipt and action in response to said second message; and

responsive to said second message, receiving said confirming message via a fourth 8B/10B encoded frame.

7. The method of claim 1, further comprising:

sending a second message via a third 8B/10B encoded frame to said module, said second message adapted to cause said module to enable communications with a communicatively coupled second module and to send a confirming message acknowledging receipt and action in response to said second message; and

responsive to a failure to receive said confirming message via a fourth 8B/10B encoded frame in response to said second message, executing a recover procedure.

8. The method of claim 1, further comprising:

sending a second message via a third 8B/10B encoded frame to said module, said second message adapted to cause said module to enable communications with a communicatively coupled second module and to send a confirming message acknowledging receipt and action in response to said second message; and

responsive to a failure to receive said confirming message via a fourth 8B/10B encoded frame in response to three unsuccessful attempts to cause said fourth 8B/10B encoded frame, executing a recover procedure.

9. The method of claim 1, further comprising:

responsive to a failure to receive said second 8B/10B encoded frame, determining that no module exists that is assigned said default module address.

10. The method of claim 1, further comprising:

responsive to three successive failures to receive said second 8B/10B encoded frame, determining that no module exists that is assigned said default module address.

11. The method of claim 1, further comprising:

receiving a response to said first message, said response comprised by a third 8B/10B encoded frame, said third 8B/10B encoded frame comprising an error code field that contains a value indicative that a message type of said first message comprised an invalid address for said module address.

12. The method of claim 1, further comprising:

sending a second message via a third 8B/10B encoded frame to said module, said second message adapted to cause said module to enable communications with a communicatively coupled second module and to send a confirming message acknowledging receipt and action in response to said second message; and

receiving a response to said second message, said response comprised by a fourth 8B/10B encoded frame, said fourth 8B/10B encoded frame comprising an error code field that contains a value indicative that communication has already been enabled to a communicatively coupled second module.

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

sending a first message from a programmable logic controller (PLC) to a module, said first message transmitted via a first 8B/10B encoded frame that comprises a destination address corresponding to an eight bit default module address of said module, said first message adapted to set a module address of said module to an assigned address value and transmit a reply message via a second 8B/10B encoded frame that comprises a source address that confirms said assigned address value has been assigned to said module by said first message, said first 8B/10B encoded frame 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 first 8B/10B encoded frame, said message type field following a first ordered sequence of fields comprised by said first 8B/10B encoded frame, 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 first 8B/10B encoded 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;

responsive to a failure to receive said reply message, sending a second message via a third 8B/10B encoded frame to said module, said second message adapted to set said module address to said default eight bit module address;

responsive to said second message, receiving a response message via a fourth 8B/10B encoded frame, said response message adapted to confirm that said module address has been reset to said default eight bit module address;

sending a third message via a fifth 8B/10B encoded frame to said module, said third message adapted to cause said module to enable communications with a communicatively coupled second module and to send a confirming message acknowledging receipt and action in response to said third message;

responsive to third second message, receiving said confirming message via a sixth 8B/10B encoded frame.

14. A system comprising:

a circuit to send a first message from a programmable logic controller (PLC) to a module, said first message transmitted via a first 8B/10B encoded frame that comprises a destination address corresponding to an eight bit default module address of said module, said first message adapted to set a module address of said module to an assigned address value and transmit a reply message via a second 8B/10B encoded frame that comprises a source address that confirms said assigned address value has been assigned to said module by said first message, said first 8B/10B encoded frame 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 first 8B/10B encoded frame, said message type field following a sequence of fields comprised by said first 8B/10B encoded 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.