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1.Check if the square
orange LED of RS485
dosen't bright.
2.Check if the square
orange LED of RS485
dose bright, but no
reply.
Check if the square
Reply wrong
orange LED of RS485
data from the
dose bright, but reply
meter
Error.
RS485 MODBUS RTU MODE
■
Modbus RTU Mode protocol
■
1. Function 03H (Read Holding Registers)
Request Data Frame; EX: Read the data of display value(0000H starts from 1 Word)
SLAVE
FUNCTION
Address
01H
03H
Response Data Frame; EX: The response value is "0"
SLAVE
FUNCTION
Address
01H
03H
Request Data Frame (EX: Continue to request the data of 10 points)
SLAVE
FUNCTION
Address
01H
03H
Response Data Frame
SLAVE
FUNCTION
Address
01H
03H
2. Writing Command by Function 06H (Preset Single Register)
Request Data Frame
SLAVE
FUNCTION
Address
Code
01H
06H
Response Data Frame
SLAVE
FUNCTION
Address
Code
01H
06H
ADDRESS TABLE **Address number are Hexadecimal
■
A.Please check the [adres](E-01)、[ baud](E-02) and
[prity](E-03) in [rs485 group] that both have to match
the Host.
B.Please check the wiring A(+) and B(-) are correct or not?
C.If user uses a converter (RS485/RS232 or RS485/USB..),
please check the setting and wiring of converter is correct.
D.Please check the protocol of host is Modbus RTU Mode
A.Please confirms the CHECH SUM program is correct.
B.Please check the interval of each command has to over
3.5byte.
A.Please check the protocol of host is Modbus RTU Mode
B.Please check the address table of RS485 to make sure that
is right address.
C.Please checks the start address and data format are correct.
D.Please do not lay the wires of RS485 together with
high-voltage lines or power lines. As a general rule, wire the
meter in a separate system, use an independent metal
conduit, or use shielded cable.
Starting
Starting
Address Hi
Address Lo
00H
00H
Byte
Data
count
Hi
02H
00H
Starting
Starting
Address Hi
Address Lo
00H
00H
Byte
Data(1)
count
Hi
14H
00H
Starting
Starting
Address Hi
Address Lo
00H
00H
Starting
Starting
Address Hi
Address Lo
00H
00H
MW-5 Operating Manual 2012-07-19
No. of
No. of
Word Hi
Word Lo
00H
01H
Data
CRC
Lo
Lo
00H
B8H
No. of
No. of
Word Hi
Word Lo
00H
0AH
Data(1)
... ... Data(10)
Lo
00H
... ...
01H
Preset
Preset
DATA Hi
DATA Lo
00H
02H
Preset
Preset
DATA Hi
DATA Lo
00H
02H
CRC
CRC
Lo
Hi
84H
0AH
CRC
Hi
44H
CRC
CRC
Lo
Hi
C5H
CDH
Data(10)
CRC
Hi
Lo
Lo
00H
--
CRC
CRC
Lo
Hi
08H
0BH
CRC
CRC
Lo
Hi
08H
0BH
CRC
Hi
--
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