IDEC FT1A Series User Manual page 281

Function Code 16 (Preset Multiple Registers)
Function code 16 changes word device data of D (data register). One through 64 consecutive words can be changed.
Communication Frame
Request from Modbus Master
Function
Slave No.
Code
xxh 10h
ACK Reply from Modbus Slave
Slave No.
xxh
NAK Reply from Modbus Slave
Slave No.
xxh
Communication Example
Purpose
Condition
RTU Mode
•
Request from Modbus Master
ACK Reply from Modbus Slave
NAK Reply from Modbus Slave
No. of
Address
Words
xxxxh xxxxh
Function Code Address
10h xxxxh
Function Code Error Code
90h xxh
Write the following data to four data registers D1708 through D1711.
D1708 D1709
(1234h) (5678h)
D1708 → (1708 – 0) + 400001 = 401709
Modbus address: 401709
Extract lower 5 digits → 1709
1709 – 1 = 1708 = 6ACh
Communication frame address: 06ACh
Slave No. 8
08 10 06AC 0004 08 12 34 56 78 AB CD EF 01 (CRC)
08 10 06AC 0004 (CRC)
08 90 xx (CRC)
S AXIS P
MART
Quantity of First High
Data
xxh
No. of Words
xxxxh
D1710 D1711
(ABCDh) (EF01h)
/L U ' M FT9Y-B1378
RO ITE SER S ANUAL
11: M
ODBUS
First Low
Byte Byte
xxh xxh
C
OMMUNICATION
Last Low
Byte
xxh
11-17