MODBUS TCP Master/Slave Communication
6.4.3 SEND Command (MODBUS Function Code Unspecified Type)
Command format
Operand
Items Settings Setting range
i Specify the operation unit. US / SS
S Specify the header of the source node data area. (Note 1)
n Specify the No. of sent data. (Note 2)
1 - 127 words
1 - 2040 bits
D1 Specify the partner station no. H1 - HF7 (1 - 247)
D2
Specify the initial address of the receiver node data area in the partner
node. (Note 1) (Note 3)
H0 - HFFFF (0 - 65535)
D3
Specify the device area in the source node to save the execution result
code (one word).
(Note 4)
(Note 1) Types of devices and transmission methods to be specified for operands [S] and [D2], and MODBUS
function codes to be used for command execution vary.
Types of device
to be specified in [S]
Transmission
method
MODBUS function codes
to be used for command execution
16 bit device
WX, WY, WR, WL, DT, LD
Register transmission
Force Multiple Coils (15)
Preset Multiple Registers (16)
1 bit device
X, Y, R, L, DT, n, LD, n
Bit transmission Force Multiple Coils (15)
(Note 2) The No. of sent data [n] is on a word basis for register transmission, and on a bit basis for bit transmission.
(Note 3) 16 bit device WX and WL; and 1 bit device X; L; DT, n; and LD, n cannot be specified for the header of the
receiver data in the partner node.
(Note 4): Devices that can be specified for D3 are: WX, WY, WR, WL, DT, LD. Saved as one word in the specified
area.
0: Normal completion
1: Communication port is being used for master communication
2: Communication port is being used for slave communication
3: No. of master communication commands that can be used simultaneously has been exceeded
4: Sending timeout
5: Response reception timeout
6: Received data error
6-12
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