Common Modbus Functions; List Of The Modbus Functions In The Fieldbus Coupler And Controller - WAGO -I/O-SYSTEM 750 User's Installation And Configuration

280 • Common MODBUS functions
Network communication

6 Common MODBUS functions

MODBUS functions from the OPEN MODBUS / TCP SPECIFICATION are
found in the application layer of the WAGO ETHERNET fieldbus cou-
pler/controller.
i
More information
More information on the OPEN MODBUS / TCP SPECIFICATION you can
find in the Internet:
http://www.modicon.com/openmbus/standards/openmbus.htm
These functions allow digital or analog input and output data to be set or di-
rectly read out of the fieldbus node.
Function code Function
FC1:
FC2:
FC3:
FC4:
FC5:
FC6:
FC7:
FC11:
FC15:
FC16:
FC23
Tab. 6-1: List of the MODBUS functions in the fieldbus coupler and controller
To execute a desired function, specify the respective function code and the ad-
dress of the selected input or output channel.
Attention
The examples listed use the hexadecimal system (i.e.: 0x000) as their numeri-
cal format. Addressing begins with 0.
The format and beginning of the addressing may vary according to the soft-
ware and the control system. All addresses then need to be converted accord-
ingly.
hexadeci-
mal
0x01 read coils
0x02 read input discretes
0x03 read multiple registers
0x04 read input registers
0x05 write coil
0x06 write single register
0x07 read exception status
0x0B get comm event counters Communication event counter
0x0F force multiple coils
0x0010 write multiple registers
0x0017 read/write multiple
registers
Description
Reading of several input bits
Reading of several input bits
Reading of several input registers
Reading of several input registers
Writing of an individual output bit
Writing of an individual output register
Reading of the first 8 input bits
Writing of several output bits
Writing of several output registers
Reading and writing of several output registers
Modular I/O System
ETHERNET TCP/IP