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Response Codes
6-6
Response Codes
6-6-1
Configuration
6-6-2
Network Relay Errors
First word
Second word
Third word
This section describes the response codes returned with responses to FINS
commands. Response codes can be used to confirm normal completion of
command execution or to troubleshoot problems when commands fail. For fur-
ther troubleshooting information, refer to SECTION 9 Troubleshooting and
Maintenance of this manual and to the operation manuals for specific Units or
Systems.
Response codes for FINS commands consist of two bytes that indicate the
result of executing a command. The structure of the response codes is shown
in the following diagram.
7
6
Bit
Main response code (MRES)
1: Relay Error Flag
The main response code (MRES) in the first byte classifies the response and
the sub-response code (SRES) in the second byte indicates details under the
MRES classification.
If bit 7 of the first byte is ON, a network relay error has occurred. Refer to 6-6-
2 Network Relay Errors for details on troubleshooting the error.
If bit 6 or 7 of the second byte is ON, an error has occurred in the PLC or com-
puter returning the response. Refer to the operation manual for the device
returning the response for details when troubleshooting the error.
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
7
6
5
4
3
Bit
0
7
6
5
4
3
Main response code (MRES)
1: Relay Error Flag
7
6
5
4
3
Error network address
Error network address:00 to 7F (Hex) (0 to 127 in decimal)
First byte
5
4
3
2
1
0
Second byte
2
1
0
7
6
5
Command code
2
1
0
7
6
5
Sub response code (SRES)
1: PLC Non-fatal Error Flag
1: PLC Fatal Error Flag
2
1
0
7
6
5
Error node address
Section 6-6
Second byte
7
6
5
4
3
2
Sub-response code (SRES)
1: PLC Non-fatal Error Flag
1: PLC Fatal Error Flag
4
3
2
1
0
0
0
4
3
2
1
0
4
3
2
1
0
1
0
177
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