Veichi Electric AC60 series Manual page 185

Command code
Error code
CRC CHK low-order
CRC CHK high-order
END
5.2.4 Communication frame error check mode
The standard ModBus serial network adopts two kinds of error check mode:
odd/even checking which is used to check every character and CRC detecting
which is used to check one frame of data.
1、 Odd-even checking
The users can configure the controller with odd or even checking, or no
checking, what will determine how to set odd/even checking in every character.
If odd /even checking have been allocated, "1" bit will be accounted to
the bit number of each character (7 bits in ASCII mode, 8 bits in RTU). For
instance, the RTU character frame contains the following 8 bits: 1 1 0 0 0 1
0 1
There are 4 bits with number"1". If using the even checking, odd/even
checking bit of the frame will be 0, then there are still 4 bits with number"1".
If using odd checking, odd/even checking bit of the frame will be 1, then there
are 5 bits with number"1".
If odd/even checking have not been allocated, there will be no checking
bit during the transmission, and no checking detection. One additional stop
bit will be filled into the character frame in transmission.
2、 CRC-16（cycle redundant check）
While the RTU frame form in use; the frame has included the frame error
detecting domain which calculates base on the CRC method. The CRC domain checks
the content of the entire frame. The CRC domain is two bytes, containing binary
88H
03H
06H
01H
Transmission time of 3.5 bytes
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