－24－
5.5.10 Write floating data
[Function code: 71 (47H)]
A specified number of "floating data (floating-point data)" from the designated numbers is programmed to
specified values. This function code is not available in the standard MODBUS. 4 bytes of data (32 bits)
constitute one floating data.
Example) Writing range value of CH No.1 of the slave unit1.
(Program 2 Reference Nos. from 50301 to 50302 of floating data to the following values for the slave
unit 1.)
Address 50301
50302
Data
0.0
(00H,00H,00H,00H)
1234.5
(44H,9AH,50H,00H)
（
RTU data
）
Master
→
Instrument
Master
→
PC
(normal)
Slave address
01H
Slave
address 01H
Function code
47H
Function
code 47H
Number of data
00H
Number of data 00H
Start No. (H)
01H
Start No. (H)
01H
Start No. (L)
2CH
Start No. (L)
2CH
Number of Reference
No. (H)
00H
Number of
Reference No. (H)
00H
Number of Reference
No. (L)
02H
Number of
Reference No. (L)
02H
Number of data
08H
CRC(L) 45H
1st data (1)
00H
CRC(H)
43H
1st data (2)
00H
1st data (3)
00H
1st data (4)
00H
Next data (1)
00H
Next data (2)
50H
Next data (3)
9AH
Next data (4)
44H
CRC (L)
47H
CRC (H)
F4H
LRC
53H
LRC 89H
Note) Data type is fixed at 00H.
Note) Start No. (Relative No.) is given by "Reference No. - 50001". (Decimal number 300 (=50301 - 50001)
Hexadecimal 12CH)
Note) No. of data is the number of data bytes.
(which is different from the requested number of data. In the example given above, the requested
number of Reference No. is 2 and the number of data is 8).
Note) Transmit the floating-point data from LSB.
(Error check in ASCII mode)
