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11: M
C
ODBUS
OM M UN I CATI ON
Function Code 15 (Force Multiple Coils)
Function code 15 changes bit device statuses of Q (output), R (shift register), or M (internal relay). One through 128 consecutive
bits can be changed.
Communication Frame
Request from Modbus Master
Function
Slave No.
Code
xxh
0Fh
ACK Reply from Modbus Slave
Slave No.
xxh
NAK Reply from Modbus Slave
Slave No.
xxh
Communication Example
Write the following bit statuses to internal relays M605 through M624.
Purpose
M605 (LSB) through M614 (MSB) binary data: 6B
M615 (LSB) through M624 (MSB) binary data: 02
M605 (60 – 0) 8 + 5 + 1001 = 1486
Modbus address: 1486
1486 – 1 = 1485 = 5CDh
Communication frame address: 05CDh
Condition
Slave No. 8
RTU Mode
Request from Modbus Master
ACK Reply from Modbus Slave
NAK Reply from Modbus Slave
11-16
Address
No. of Bits
xxxxh
xxxxh
Function Code
Address
0Fh
xxxxh
Function Code
Error Code
8Fh
xxh
M610
M611
M612
(ON)
(OFF)
(ON)
M620
M621
M622
(OFF)
(OFF)
(OFF)
08 0F 05CD 0010 02 6B 02 (CRC)
08 0F 05CD 0010 (CRC)
08 8F xx (CRC)
S
A XI S P
M AR T
Quantity of
First
Data
8 Bits
xxh
No. of Bits
xxxxh
M613
M614
(ON)
(OFF)
M623
M624
(OFF)
(OFF)
/ L
U
'
M
FT9Y-B 1378
R O
I TE
SER
S
ANUAL
Second
8 Bits
xxh
xxh
M607
M605
M606
(ON)
(0N)
(OFF)
M617
M615
M616
(OFF)
(0N)
(OFF)
Last
8 Bits
xxh
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Troubleshooting
