EC5000
- 96 - - 97 -
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