WF-2000 Series AIO
User’s Manual (RevB1.0, Oct./2016) ------------- 46
Table
4-1 Modbus request command list
Request
FC1 Read
multiple coils
status (0xxxx) for
DO
FC2 Read
multiple input
discrete (1xxxx)
for DI
FC3 Read
multiple
registers
(4xxxx) for AO
FC4 Read
multiple input
registers
(3xxxx) for AI
FC15 Force
multiple coils
(0xxxx) for DO
FC16 Write
multiple
registers
(4xxxx) for AO
Byte 0
Net ID
Byte 1
FC=0x01
FC=0x02
FC=0x03
FC=0x04
FC=0x0F
FC=0x10
Byte 2-3
Reference number
Byte 4-5
Bit count
Bit count
Word count
Word count
Bit count
Word count
Byte 6
N/A
N/A
N/A
N/A
Byte count (B)
Byte count (B)
Byte 7-( B+6)
N/A
N/A
N/A
N/A
Data to be
written
Register values
d. Modbus TCP request command examples.
Figure
4-13 Read multiple coils status (0xxxx) for DO
Figure
4-14 Force multiple coils (0xxxx) for DO
Figure
4-15 Read multiple input discretes (1xxxx) for DI
Figure
4-16 Read multiple input registers (3xxxx) for AI
Figure
4-17 Read multiple registers (4xxxx) for AO
