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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

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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