Integer Byte Order; Float Byte Order; Modbus Function Codes - Siemens SITRANS F Operating Instructions Manual

Modbus communication
A.7 Modbus function codes
A.5

Integer byte order

The device is able to adjust the byte order of integer values.
Table A-4 Integer byte order
Modbus Data type /
register Size in
bytes
8295 Unsigned /
2
A.6

Float byte order

The device is able to adjust the byte order of floating-point values.
Table A-5 Float byte order
Modbus Data type /
register Size in
bytes
8296 Unsigned /
2
A.7

Modbus function codes

Table A-6 General Modbus settings
Function code Command text
01 Read Coils
02 Read Discrete Inputs
78
Parameter Description
Integer order byte The integer byte order used
in Modbus messages.
0: MSB - LSB (big endian)
1: LSB - MSB (little endian)
MSB = most significant byte /
high byte
LSB = least significant byte /
low byte
Parameter Description
Float byte order The float byte order used in
Modbus messages.
0: 1-0-3-2
1: 0-1-2-3
2: 2-3-0-1
3: 3-2-1-0
The first mentioned byte is
the first byte sent.
Byte 3 corresponds to the
left-most byte (MSB) of a 32
bit floating point number in
big endian format, byte 0 to
the right-most byte
Default value
[units]
(units register)
MSB - LSB
(big endian)
Default value
[units]
(units register)
3-2-1-0
Description
Reads the status of single bit(s)
Reads the status of single input bit(s)
Operating Instructions, 09/2017, A5E41425845-AB
Value range / Access
Setting op‐ level
tions
0 - 1 Read /
write
Value range / Access
Setting op‐ level
tions
0 - 3 Read /
write
FST020 IP65 NEMA 4X