Vaisala HMP110REF User Manual

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
10
hex
10
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 55
hex
Modbus RTU
checksum
CC
hex
Value for the first
register (least
significant word)
68
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
5E
hex
Modbus RTU
checksum
96
hex
(silence for 3.5 bytes) End of Modbus RTU
frame
Communication description
Register number 785 (1-based Modbus register number) = address 0310
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
.
Appendix A – Modbus reference
93

Vaisala HMP110REF Specifications

General

Brand	Vaisala
Model	HMP110REF
Category	Measuring Instruments
Language	English