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6.3.2 RECV Command (MODBUS Function Code Specified Type)
Command format
Operand
Items
Settings
i
Specify the operation unit.
Specify the MODBUS function codes and partner station no. to be used. (Note 1) (Note 2)
Higher
S1
byte
Lower
byte
S2
Specify the source MODBUS address in the partner node.
n
Specify the No. of sent data. (Note 3)
Specify the device initial address of the receiver node data area in the
D1
source node. (Note 2)
Specify the device area in the source node to save the execution result
D2
code (one word).
(Note 1) Operand [S1] is specified by combining two hexadecimal digits of MODBUS function code with two
hexadecimal digits of partner station no.
E.g. Specify "H030F" when MODBUS function code is 03 (Read Holding Registers) and station no. is 15.
(Note 2) Based on the types of device specified in operand [D1], the transmission methods and MODBUS function
codes that can be used vary.
Device to be specified
for [D1]
16 bit device
WX, WY, WR, WL, DT, LD
1 bit device
X, Y, R, L, DT, n, LD, n
(Note 3) The No. of sent data is on a word basis for register transmission, and on a bit basis for bit transmission.
(Note 4): Devices that can be specified for [D2] 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
6.3 MODBUS TCP Master Communication (RECV)
Two hexadecimal digits that indicate the MODBUS
function code
Two hexadecimal digits that indicate the station no.
Transmission
method
Register
transmission
Bit transmission
US / SS
H1 - H4 (1 - 4)
H1 - HF7 (1 - 247)
H0~HFFFF (0 - 65535)
1 - 127 words
1 - 2040 bits
-
(Note 3)
Values that can be specified in higher
bytes of [S1]
H1: Read Coil Status (01)
H2: Read Input Status (02)
H3: Read Holding Registers (03)
H4: Read Input Registers (04)
H1: Read Coil Status (01)
H2: Read Input Status (02)
Setting range
6-7
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