Supported Function Codes; Function Code 3, Read 16-Bit Parameter - BONFIGLIOLI Vectron ACTIVE Manual

6.4 Supported Function Codes

Modbus definitions for reading/writing data in a device do not fit directly to parame-
ter access of inverters (independent of inverter manufacturer). Modbus is defined for
reading/writing bits and registers in a different way. Furthermore, data access is
limited to 16 bit wide data.
To fulfill the Modbus requirements the data access to parameters in the devices (in-
verters) will use the following defined function codes:
-
-
For data access to 32 bit wide data two new inverter specific function codes are
defined:
-
-
With the help of these two new functions (which are not defined by the Modbus
descriptions), data access to 32-bit "long" variables/parameters inside the inverters
is made possible.
For diagnostic purposes the Modbus function code "8" (
ported.
These function codes and their corresponding data fields are described in detail in
the following chapters.
Remark: In all data fields with more than one byte, the highest order byte is
transmitted first.
Message examples for all supported function codes in both RTU and ASCII transmis-
sion modes can be found in chapters 8.

6.4.1 Function Code 3, Read 16-bit Parameter

This function code is used to read the value of integer or unsigned integer parame-
ters in the inverter.
Request:
Function Code
Start Address (Data Set / Para-No.)
No. of Registers
Response:
Function Code
Byte Count
Register Value (Parameter Value)
Exception Response:
Error Code
Exception code
20
20
Function Code 3
Function Code 6
Function Code 100
Function Code 101
Modbus Instruction manual
Modbus Instruction manual
Read ONE 16 bit wide data
Write ONE 16 bit wide data
Read ONE 32 bit wide data
Write ONE 32 bit wide data
1 Byte
2 Bytes
2 Bytes
1 Byte
1 Byte
2 Bytes
1 Byte
1 Byte
(Read Holding Register)
(Write Single Register)
Diagnostics
) is also sup-
0x03
0x0000 – 0x963F
0x0001 (always)
0x03
0x02 (always)
0 – 0xFFFF
0x83
2, 3 or 4
05/08
05/08