
COOLMAY EX3G PLC/HMI All in one Programming manual
39
b0
Data length
0:7 bit
1:8 bit
b2
b1
Parity
00:None
01:Odd
11:Even
b3
Stop bit
0:1 bit
1:2 bit
b4
b5
b6
b7
Baud rate (b7b6b5b4)
0100:600bps
0101:1200bps
0110:2400bps
0111:4800bps
1000:9600bps
1001:19200bps
1010:38400bps
1011:57600bps
1100:115200bps
Demo Program:
Use the serial port tool by serial port 2 to monitor the data obtained:
[2017:11:01:10:49:16][receive]31 32 33
2.11.1.3 Modbus RTU Protocol
When used as MOdbus RTU
:
set M8196=1,M8125=1; set D8120 as communication parameters, D8121 set
as slave station. For example: D8120=HE081
,
D8121=H1
(
communications parameter as 9600/8/n/1
,
station
number is 1
)
When PLC is as host, ADPRW,RD3A and WR3A is supported.
RD3A and WR3A only support the below MODBUS functions:
Hold register readout (function code: 0x03),
Register write (function code: 0x06),