WAGO 750-830 Manual page 215

Therefore the MODBUS protocol based essentially on the following basic
data types:
Data type
Discrete Inputs
Coils
Input Register
Holding Register
For each basic data type one or more „Function codes" are defined.
These functions allow digital or analog input and output data, and internal
variables to be set or directly read out of the fieldbus node.
Function code
FC1:
FC2:
FC3:
FC4:
FC5:
FC6:
FC 11:
FC 15:
FC 16: 0x0010 Write Multiple
FC 22: 0x0016 Mask Write
FC 23: 0x0017 Read/Write
Tab. 4-3: List of the MODBUS Functions in the Fieldbus Controller
To execute a desired function, specify the respective function code and the
address of the selected input or output data.
Attention
The examples listed use the hexadecimal system (i.e.: 0x000) as their numerical
format. Addressing begins with 0.
The format and beginning of the addressing may vary according to the software
and the control system. All addresses then need to be converted accordingly.
WAGO-I/O-SYSTEM 750
BACnet/IP Controller
Length
1 Bit
1 Bit
16 Bit
16 Bit
Function
hexadec.
0x01 Read Coils
0x02 Read Input
Discretes
0x03 Read Multiple
Registers
0x04 Read Input
Registers
0x05 Write Coil
0x06 Write Single Writing of an individ
Register ual output register
0x0B Get Comm
Event Count-
ers
0x0F Force Multiple
Coils
Registers
Register
Registers
Fieldbus Communication
Description
Digital Inputs
Digital Outputs
Analog-Input data
Analog-Output data
Access method and
description
Reading of several R: Process image, PFC variables
single input bits
Reading of several R: Process image, PFC variables
input bits
Reading of several R: Process image, PFC variables, in-
input registers ternal variables, NOVRAM
Reading of several R: Process image, PFC variables, in-
input registers ternal variables, NOVRAM
Writing of an indi- W: Process image, PFC variables
vidual output bit
W: Process image, PFC variables, in-
ternal variables, NOVRAM
Communication R: None
event counter
Writing of several W: Process image, PFC variables
output bits
Writing of several W: Process image, PFC variables, inter-
output registers nal variables, NOVRAM
W: Process image, PFC variables,
NOVRAM
Reading and writ- R/W: Process image, PFC variables,
ing of several out- NOVRAM
put registers
MODBUS Functions
Access to resources
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