Vaisala DRYCAP DMT143 - Page 84

Writing Filtering Factor Value
Request Response
Bytes on the Line
(Hexadecimal)
Description Bytes on the Line
(Hexadecimal)
Description
(silence for 3.5 bytes) Start of Modbus RTU
frame
(silence for 3.5 bytes) Start of Modbus RTU
frame
F0
hex
Transmitter address F0
hex
Transmitter address
10
hex
Function (Write
Multiple Registers)
10
hex
Function (Write
Multiple Registers)
03
hex
Register address 03
hex
Register address
1A
hex
1A
hex
00
hex
Number of registers to
write (2)
00
hex
Number of 16-bit
registers written (2)
02
hex
02
hex
04
hex
Number of data bytes 75
hex
Modbus RTU
checksum
CC
hex
Value for the first
register (least
significant word)
6A
hex
CD
hex
(silence for 3.5 bytes) End of Modbus RTU
frame
3E
hex
Value for the second
register (most
significant word)
The response to a write
function informs that the
function was correctly received
by the device. It does not
guarantee that the written
value was accepted by the
device (for example, in case of
out-of-range values).
To verify that the value was
really accepted by the device,
read the register value after
writing.
4C
hex
DE
hex
Modbus RTU
checksum
E9
hex
(silence for 3.5 bytes) End of Modbus RTU
frame
Communication Description
Register number 795 (1-based Modbus register number) = address 031A
hex
(0-
based address used in actual communication).
Data format Two 16-bit Modbus registers interpreted as IEEE 754 binary32
floating point value, least significant word first.
Value to write 0.2, in binary32 format 3E4CCCCD
hex
.
DMT143 User Guide M211435EN-J
82