Modbus remote i/o communication module rtu-485, 6application of rtu-485, 1 connection between rtu-485 and master device – Delta Electronics Communication Module RTU-485 User Manual
Page 11: 2 application example, Dvp-plc application manual 9, Special module
Modbus Remote I/O Communication Module RTU-485
DVP-PLC Application Manual
9
6
Application of RTU-485
6.1 Connection between RTU-485 and Master Device
As a standard Modbus slave, RTU-485 is compatible with pther programmable logic controllers which also
comply with Modbus protocol. The example here takes DVP-SV PLC as the master. The PC downloads the
ladder diagram to DVP-SV through RS-232 communication port (COM1). When DVP-SV executes the ladder
diagram program, it will send out Modbus command through RS-485 communication port (COM2) and conduct
remote I/O control on RTU-485. See the figure on the next page for the connection between RTU-485 and the
master device:
DVP28SV
RUN
STOP
D
V
P
-0
2
D
A
D
V
P
-0
8
S
T
D
V
P
-1
6
S
P
D
V
P
-0
4
A
D
D
V
P
-0
4
T
C
D
V
P
-0
4
P
T
R
T
U
-4
8
5
RS-485
CO M2
RTU-485
Slim
DI/DO
Special
module
DVP-SV
6.2 Application Example
Example
1
¡ The station No. of RTU-485 is “1”. Write “H’0001” into CR#6 of the 1
st
special module.
Set up communication protocol
9600,7,E,1,ASCII
MOV
K300
D1129
M1002
SET
M1120
M0
SET
M1122
M0
MODWR
K1
H1606
H0001
END
RST
M1143
M1123
RST
M1123
M1129
RST
M1129
Retain communication protocol
Set up communication time-out 300ms
Set up sending request
Write H0001 into CR#6 of
the 1 special module
st
Process received data
Receiving of data is completed.
The flag is reset.
Process communication time-out
MOV
H86
D1120