WAGO-I/O-SYSTEM 750 XTR
Fieldbus Communication 163
750-352/040-000 FC ETHERNET G3 XTR
Manual
Version 1.3.0
Pos: 94.12 /Serie 750 ( WAGO-I/O-SYST EM)/Funkti onsbeschrei bung/F eldbuskommuni kation/M ODBU S/Anwendung der MOD BUS-F unktionen - FC11, FC15, FC 16 @ 4\mod_1235567470328_21.docx @ 27730 @ 444 @ 1
11.2.3.7 Function Code FC11 (Get Comm Event Counter)
This function returns a status word and an event counter from the slave device’s
communication event counter. By reading the current count before and after a
series of messages, a master can determine whether the messages were
handled normally by the slave.
Following each successful new processing, the counter counts up. This counting
process is not performed in the case of exception replies, poll commands or
counter inquiries.
Request
Table 91: Request of Function code FC11
Byte
Field name
Example
Byte 0, 1
Transaction identifier
0x0000
Byte 2, 3
Protocol identifier
0x0000
Byte 4, 5
Length field
0x0002
Byte 6
Unit identifier
0x01 not used
Byte 7
MODBUS function code
0x0B
Response
The reply contains a 2-byte status word and a 2-byte event counter. The status
word only contains zeroes.
Table 92: Response of Function Code FC11
Byte
Field name
Example
...
Byte 7
MODBUS function code
0x0B
Byte 8, 9
Status
0x0000
Byte 10, 11
Event count
0x0003
The event counter shows that 3 (0x0003) events were counted.
Exception
Table 93: Exception of Function Code FC 11
Byte
Field name
Example
...
Byte 7
MODBUS function code
0x85
Byte 8
Exception code
0x01 or 0x02
