9
Modbus protocol (Modbus/TCP)
Protocol structure
Manual – MOVIPRO
®
with EtherNet/IP™ or Modbus/TCP Fieldbus Interface
107
9.2.5 Service FC43 – Read device identifications
The service "FC43–Read device identifications" is also referred to as MEI transport
(Modbus Encapsulated Interface Transport). It tunnels services and method calls. The
service "Read device identification" is tunneled with the MEI-Type 0x0E. In accord-
ance with Modbus specifications, there are 3 blocks ("Basic", "Regular" and "Exten-
ded") that can be read.
The device supports "Basic" and "Regular" blocks (Conformity Level 02). The entire
block is always read (streaming). This means that values "01" and "02" are permitted
in the "Read device ID code". The "Object ID" must have the value "0". The response
is not fragmented.
Example
Request:
Byte Designation Meaning/permitted values
0–6 MBAP header See chapter "Header"(→2103)
7 Function code
Requested service
Value: 43 (Read Device Identification)
8 MEI type Value: 0x0E
9 Read device ID code Value: 01 or 02
10 Object ID Value: 0
Response:
Byte Designation Meaning/permitted values
0–6 MBAP header See chapter "Header"(→2103)
7 Function code
Service
Value: 43 (Read Device Identification)
8 MEI type Value: 0x0E
9 Read device ID code Value: 01 or 02
10 Conformity level Value: 02
11 More follows
If the identification data does not fit on one response,
several request/response transactions are required.
Value: 0 (no further requests)
12 Next object ID Value: 0
13 Number of objects
Number of objects
Value (example): 3
14 Object ID ID of first object
15 Object length Length of first object in bytes
16 Object value Value of first object
17–Number of objects
x 2
1)
Object ID, object length,
and object value of all
other objects
2)
–
1) In the example up to 22
2) In this example, 2 more objects
Exception:
Byte Designation Meaning/permitted values
0–6 MBAP header See chapter "Header"(→2103)
7 Function code 43
hex
8 Exception code Error code
16998413/EN – 12/2016
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