Delta Electronics Communication Module RTU-485 - Manual (Page 12)

Modbus Remote I/O Communication Module RTU-485
DVP-PLC Application Manual 10
¡ Explanations
1. You have to set up the communication format at the beginning of the program. The communication
format for the master and slave has to be consistent, e.g. you can see the format is 9600, 7, E, 1,
ASCII from this example.
2. After setting up the communication format, you have to set up the communication retention device
M1120 of COM2.
3. After M0 is On, set up the sending request flag, and the master device will send out a request
message to RTU-485 and write H’0001 into CR#6 of the 1
st
special module on the right hand side of
RTU-485.
„ Example 2
¡ The station No. of RTU-485 is “1”. Set up Y0 of the Slim DI/DO on the right hand side of RTU-485.
MOV K300 D1129
M1002
MOV H86
SET M1120
RST M1143
MOV
MOV
MOV
H303A D100
H3031 D101
H3035 D102
MOV
MOV
H3035 D103
H4630 D104
MOV
MOV
H3046 D105
H4630 D106
MOV
MOV
H D107
HA D108
M0
SET M1122
M0
RS D100 K17 D120 K17
M1123
RST M1123
PLC sends out
01 05 05 00 FF 00 F6 CR LF ": "
D36
Set up communication protocol
9600, 7, E, !, ASCII
Retain communication protocol
Set up communication time-out 300ms
to RTU-485
Set up sending request
When M0 = On, the 17 words in D100 ~ D108 will be sent out.
The 17 words responded by RTU-485 will be stored in D120 ~ D128 by the master.
Process received data
Receiving of data is completed.
The flag is reset.
D1120