Delta C2000 series User Manual page 345

Chapter 12 Description of Parameter Settings|C2000 Series
Number of data
(count by byte)
The first data content
The second data content
LRC Check
END
RTU mode:
Command Message:
ADR
CMD
Starting data address
Number of data
(count by word)
Number of data
(count by byte)
The first data content
The second data content
CRC Check Low
CRC Check High
Check sum
ASCII mode:
LRC (Longitudinal Redundancy Check) is calculated by summing up, module 256, and 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,
01H+03H+21H+02H+00H+02H=29H, the 2's-complement negation of 29H is D7H.
RTU mode:
CRC (Cyclical Redundancy Check) is calculated by the following steps:
Step 1:
Load a 16-bit register (called CRC register) with FFFFH.
Step 2:
Exclusive OR the first 8-bit byte of the command message with the low order byte of the 16-bit CRC
register, putting the result in the CRC register.
Step 3:
Examine the LSB of CRC register.
Step 4:
'0'
LRC Check
'4'
'1'
'3'
'8'
'8'
'0'
'F'
'A'
'0'
'9'
'A'
CR
LF
01H
10H
05H
Starting data address
00H
00H
Number of data
(count by word)
02H
04
CRC Check Low
13H CRC Check High
88H
0FH
A0H
'9'
'A'
12-138
END
Response Message
ADR
CMD 1
'E'
'8'
CR
LF
01H
10H
05H
00H
00H
02H
41H
04H