abc 2000 Series User Manual page 179

message.receive messages the device recalculate.And compared
with receives the CRC in the domain of value, if the
is not equal, then there is an error in transmission.
CRC is saved in OxFFFF,Than call a process to continuous 8-bit
bytes of the message and the values in the current register
for processing.Only 8 bit data in each character of CRC is
effective.Starting bit and stopping bit and parity bits are invalid.
In the process of CRC,Each of the eight characters are separate
and dissimilar or register oontents(XOR), The results move to the
least significant bit direction, set the most signtficant bit to 0. LSB is
extracted to test,
or alone.if set LSB to 0, is not to.The whole process will repeat 8
times.when the last time ( the eighth lime) is oompleted,nexl 8-bit
bytes and separate and register under the current value of the alien
or.The values in the final register,ls all bytes in the message is
executed after the CRC value.
Whan CRC added to the massages .The low by!& to join first and
then high byte.CRC Simple function is as follows:
unsigned int c:rc_cal_value(unsigned char *data_value,unsigned
char data_length)
{
inti;
unsigned int crc_value=Oxfff f ;
while{data_length--)
{
crc_valueA=*data_va!ue++;
for(i=O;i<8;i++)
{
lf(crc_ value&Ox0001 )
crc_value=(crc_ value>>1 )"Oxa001 ;
else
crc_value=crc_value>>1;
l
)
Retum{crc_value);
}
Address definition of communication parameters
This part is the content of the communication, used to control the
operation of the inverter, inverter status and related parameters
setting.Read and write functional code parameter (some function
if
set LSB to 1,Register and preset value dissimilarity
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two
CRC value