4 Modbus
TCP
Festo – GDCP-CMMO-ST-LK-C-HP-EN – 2017-05b – English
27
Modbus
command
Significance
Read device
identification
Read the device data
Read device identification request (0x2B)
Field
Bytes
Values
Byte no.
Function code
1
0x2B
8
MEI type
1
0x0E
9
Read device ID code
1
0x01: basic device identification
0x02: regular device identification
10
Object ID
1
0x00: (first object to be transferred)
11
Read device identification response (0x2B)
Field
Bytes
Values
Byte no.
Function code
1
0x2B
8
MEI Type
1
0x0E
9
Read device ID code
1
Same as request field
10
Conformity level
1
0x01: basic device identification
0x02: regular device identification
11
More follows
1
0x00: no more objects
12
Next object ID
1
0x00
13
No. of objects
1
Number of objects in this message
14
Object 1
1
è
15 ...
...
...
Object n
1
Read device identification exception (0xAB)
Field
Bytes
Values
Byte no.
Error code
1
0xAB
8
Exception code
1
0x01: illegal function
0x02: illegal data address
0x03: illegal data value
0x04: server device failure
9
Tab. 4.3
Overview of Modbus function codes
Содержание CMMO-ST-C5-1-LKP
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