Chapter 5 Parameters
|
VFD-B Series
Revision July 2008, BE16, SW V4.08 & V5.00
5-89
RTU mode:
Command message:
Response message:
Address 01H
Address 01H
Function 10H
Function 10H
05H
05H
Starting data
address
00H
Starting data address
00H
00H’
00H
Number of data
(count by word)
02H
Number of data
(count by word)
02H
Number of data
(count by byte)
04
CRC Check Low
41H
13H
CRC Check High
04H
The first data
content
88H
0FH
The second data
content
A0H
CRC Check Low
‘4D’
CRC Check High
‘D9’
3.4 Check sum
ASCII mode:
LRC (Longitudinal Redundancy Check) is calculated by summing up, module 256, the values of
the bytes from ADR1 to last data character then calculating the hexadecimal representation of the
2’s-complement negation of the sum.
For example, reading 1 word from address 0401H of the AC drive with address 01H.
STX ‘:’
‘0’
Address 1
Address 0
‘1’
‘0’
Function 1
Function 0
‘3’
‘0’
‘4’
‘0’
Starting data address
‘1’
‘0’
‘0’
‘0’
Number of data
‘1’
‘F’
LRC Check 1
LRC Check 0
‘6’
CR
END 1
END 0
LF
01H+03H+04H+01H+00H+01H=0AH, the 2’s-complement negation of 0AH is
F6
H.
RTU mode:
Address
01H
Function
03H
21H
Starting data address
02H