©2016 DEKIST Co., Ltd. Rev. 1.6
9. MODBUS TCP Protocol Definition
It is possible to read the currently measured data from RN171 through MODBUS TCP communication. The
data is updated to
“
HOLDING REGISTER
”
in real time. The 4 BYTE FLOATING POINT and 2 BYTE UNSIGNED
INT formats are supported. Reading is possible. In the case of 2 BYTE UNSIGNED INT, the decimal digits
are ignored, and only the integers are delivered.
Transaction ID, Protocol ID, and Unit ID are internally ignored. Whatever value you input through them,
they will use 3 as the function code.
READ HOLDDING REGISTER, FUNCTION CODE: 3
Channel
Address Index
16Bit
16Bit
(Byte Reverse)
Value
CH1
4 Byte Floating
0
0x3333
0x3333
27.9
1
0x41df
0xdf41
CH2
4 Byte Floating
2
0x999a
0x9a99
29.2
3
0x41e9
0xe941
CH1
2Byte Unsigned INT
4
0x001b
0x1b00
27
CH2
2Byte Unsigned INT
5
0x001d
0x1d00
29
[The byte sequence of the register map inside RN171, and the data bytes]
