EACON EC5000 Series, User Manual, Page: 52 / 72

EC5000
-
96
- -
97
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MODBUS Communication Protocol
6
(4)8N1 For RTU F03=3
8 - data bits Character String
11 bits Character Frame Length
Start bit 0 1 2 3 4 5 6
Stop bit
7
(5)8E1 For RTU F03=4
Even parity
8 - data bits Character String
11 bits Character Frame Length
Start bit 0 1 2 3 4 5 6
Stop bit
7
(6)8O1 For RTU F03=5
Odd parity
8 - data bits Character String
11 bits Character Frame Length
Start bit 0 1 2 3 4 5 6
Stop bit
7
6.2 Data Format Frame
■ ASCII Mode:
STX Starting Character = ‘: ’ (3AH)
Address Hi
Address Lo
Communication Address:
8-
bit address consisting of 2 ASCII codes
Function Hi
Function Lo
Function Code:
8-
bit function code consisting of 2 ASCII codes
DATA (n
-1)
…….
DATA 0
Data Content:
n×8
-
bit data content consisting of 2n ASCII codes
n<=20, maximally 40 ASCII codes(twenty data)
LRC CHK Hi
LRC CHK Lo
LRC Check Code:
8-
bit check code consisting of 2 ASCII codes
END Hi
END Lo
Ending Character:
END Hi = CR (0DH), END Lo
= LF(0AH)
6.1 Communication Data Structure:
EC5000
(1)7N2 For ASCII F03=0
7- data bits Character String
10 bits Character Frame Length
Start bit 0 1 2 3 4 5 6
Stop bit Stop bit
(2)
7E1 For ASCII F03=1
Even parity
7 - data bits Character String
10 bits Character Frame Length
Start bit 0 1 2 3 4 5 6
Stop bit
(3)
7O1 For ASCII F03=2
Odd parity
7 - data bits Character String
10 bits Character Frame Length
Start bit
0
1 2
3
4
5 6
Stop bit
MODBUS Communication Protocol
■
RTU Mode:
START Keep the no input signal for
≥
10 ms
Address Communication Address: 8
-
bit binary address
Function Function Code: 8
-
bit binary address
DATA (n
-1)
…….
DATA 0
Data Content:
n ×8
-
bit Data, n
≤
40(twenty 16
-
bit data)
CRC CHK Low
CRC CHK High
CRC Check code:
16
-
bit CRC Check code consisting of 2 8
-
bit Binary
END Keep the no input signal
≥
10 ms