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5.3 Modbus
FIG. 23 - Modbus Kit
Features
1.
"Modbus Gateway" is a slave device.
2.
The RS485 standard is robust to noise and interference, but the higher the distance the shorter the transmission rate.
Maximum distance is 1200 meters. Distance to maintain maximum transmission rate is up to 12 meters.
3.
Standard format Request Frame (TX):
Address
1 byte
4.
The setting of the DIP existing in Gateway should be carried out as follows (as indicated by the dashed lines):
8
7
Check
0
0
1
0
1
0
1
1
Function
Recorder Start
1 byte
6
5
Transmiss
ion Rate
0
0
0
1
0
1
1
1
...
RTU MODBUS COMMUNICATION PROTOCOL
The system communication is performed serially in
RS-485 standard, with enclosed protocol. To convert
to Modbus RTU protocol, the K35402026 converter
should be used (called Gateway).
2 bytes
4
3
2
Address
0
0
0
0
0
0
0
0
1
0
0
1
0
1
0
0
1
0
0
1
1
0
1
1
1
0
0
1
0
0
...
...
1
1
1
IMPORTANT
No. Recorders
2 bytes
1
Description
No parity, 2 stop bit
Even, 1 stop bit
Odd, 1 stop bit
No check, 2 stop bit
19200
9600
4800
2400
0
Gateway Address 1
1
Gateway Address 2
0
Gateway Address 3
1
Gateway Address 4
0
Gateway Address 5
1
Gateway Address 6
0
Gateway Address 7
1
Gateway Address 8
0
Gateway Address 9
1
Gateway Address 10
...
... up until ...
1
Gateway Address 16
CRC
2 bytes
43
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