SEW-Eurodrive MOVIPRO Ethernet/IP - Page 96

8
Configuration and startup of Modbus/TCP
Project planning examples
Manual – MOVIPRO
®
with EtherNet/IP™ or Modbus/TCP Fieldbus Interface
96
Process data exchange
The process data exchange is performed either via FC3 (read) and FC16 (write), or
FC23 (read and write).
Process data exchange via FC16
The Modbus/TCP part for writing of 3 process data words (setpoints) each via FC16 to
port 502 of a Modbus/TCP slave is structured as follows:
Byte Value Meaning Interpretation Help
0
0x00 Transaction identifier
–
For detailed description see
Modbus/TCP specification
and chapter "Modbus
protocol (Modbus/
TCP)"(→2101).
1
2
0x00 Protocol identifier
3
4 0x00
Length field
Number of bytes after byte 5
Value: Number of PD × 2 + 7
(In this case: 3 × 2 + 7 = 13)
5 0x0d
6 0xFF Device identifier Must be 0 or 255.
7 0x10 Function code Service: FC16 (Write Register)
8 0x00
Write reference number
Offset where PD start.
Must always be 4.
9 0x04
10 0x00
Write word count
Number PD
1)
(In this case: 3)
11 0x03
12 0x06 Write byte count
Number PD× 2
2)
(In this case: 3 x 2= 6)
13 0x00
Data Process output data word 1
Data mapping and definition,
see chapter "Process data
description"(→2118)
14 0x11
15 0x22
Data Process output data word 2
16 0x33
17 0x44
Data Process output data word 3
18 0x55
1) for MOVIPRO® SDC (1–8) for MOVIPRO® ADC (1–120)
2) for MOVIPRO® SDC (2–16) for MOVIPRO® ADC (2–240)
Response telegram
Only bytes 0 – 11 are reset in the response telegram from port 502 of the Modbus/
TCP slave.
Apart from byte 5, all values remain unchanged. Byte 5 (low byte in length field) is cor-
rected to value 6.
16998413/EN – 12/2016