Bedford B550-2002 - ASCII Mode; Code Meaning; Data Format; RTU Mode

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 Either ASCII or RTU Modbus protocols are used for communication. Users can select
the desired mode along through parameters Pr.92 and Pr.113.
 Each
B550 AC drive has a pre-assigned communication address specified by Pr.88.
The master controller communicates with each AC drive according to its particular
address.
 Code Meaning:
ASCII mode:
Each 8-bit data is the combination of two ASCII characters. For example, a 1-byte data:
64 Hex, shown as ‘64’ in ASCII, consists of ‘6’ (36Hex) and ‘4’ (34Hex).
Character ‘0’ ‘1’ ‘2’ ‘3’ ‘4’ ‘5’ ‘6’ ‘7’
ASCII code 30H 31H 32H 33H 34H 35H 36H 37H
Character ‘8’ ‘9’ ‘A’ ‘B’ ‘C’ ‘D’ ‘E’ ‘F’
ASCII code 38H 39H 41H 42H 43H 44H 45H 46H
RTU mode:
Each 8-bit data is the combination of two 4-bit hexadecimal characters. For example, 64
Hex.
 2. Data Format
2.1 10-bit character frame (For 7-bit character):
( 7.N.2 : Pr.92=0)
( 7.E.1: Pr.92=1)
Start
bit
0123456
Stop
bit
10-bit character frame
( 7.O.1:Pr.92=2)
Odd
parity
Start
bit
0
12
3456
Stop
bit
10-bit character frame
Even
parity
Start
bit
01234
5
6
Stop
bit
7-bit character
10-bit character frame
Stop
bit
7-bit character
7-bit character
B550 Series sensorless vector frequency drive