Response Codes

Section 6-7

6-7-2 Network Relay Errors

A network relay error will occur whenever a command cannot reach the desti- nation. These errors can occur for several reasons: 1) Data was not success- fully passed between two Link Units, 2) Data was not passed successfully between a Link Unit and another Unit, such as the PLC’s CPU Unit, or 3) The destination of a gateway does not exist. In any case, the Unit that was not able to transfer data will return a response indicating a network relay error.

Bit 7 of the first byte of the response code will be ON if a network relay error has occurred. When this happens, two more bytes of data will follow the response code to indicate the location of the error. This information, along with the response code, should enable you to track the error.

First byte

Second byte

Bit

First word

Second word

Third word

7

6

5

4

3

 

2

1

 

0

7

6

5

4

3

2

 

1

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Command code

 

 

 

 

 

 

 

 

 

 

 

 

7

6

5

4

3

 

2

1

 

0

7

6

5

4

3

2

 

1

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Main response code (MRES)

 

 

 

 

 

Sub response code (SRES)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1: Relay Error Flag

 

 

 

 

 

 

 

 

1: PLC Non-fatal Error Flag

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1: PLC Fatal Error Flag

 

 

 

7

6

5

4

3

 

2

1

 

0

7

6

5

4

3

2

 

1

 

0

 

 

 

 

 

Error network address

 

 

 

 

 

 

 

Error node address

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Error network address:

00 to 7F (Hex) (0 to 127 in decimal)

 

Error node address:

Controller Link: 01 to 3E

(Hex) (1 to 62 in decimal)

 

 

Ethernet:

01 to 7E

(Hex) (1 to 126 in decimal)

 

 

SYSMAC NET: 01 to 7E

(Hex) (1 to 126 in decimal)

 

 

SYSMAC LINK: 01 to 3E

(Hex) (1 to 62 in decimal)

Relay Errors

A relay error indicates that the command did not reach the Unit to which it was

 

sent. There are several types of situation in which this can occur. Example 1

 

(below) shows a situation in which a relay error occurs when data cannot be

transferred from one Communications Unit to another in an interconnected network. Example 2 shows a similar situation, except that the destination Unit is something other than a Communications Unit. In Example 3, the relay error occurs because either the specified destination node or the next relay node does not exist.

In the three diagrams, the numbers indicate the following: (1)The transmitted data fails to be received.

(2)The relay error and response code are returned to the command source.

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Omron C200HW-CLK21, CVM1-CLK21, CS1W-RPT01, CJ1W-CLK21-V1, CQM1H-CLK21, CS1W-CLK21-V1 operation manual Network Relay Errors
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