Service manual

www.enc.net.cn/en Tel/Fax:[phone] Modbus communication protocol
134
11.8 CRC checksum mode
CRC checksum value calculating function written by C language is as
follows:
unsigned int cal_crc_value (unsigned char *pval, unsigned char len)
{
unsigned int crc_value=0xFFFF;
unsigned int i;
while(len--)
{
crc_value ^= *pval++;
for(i=0; i<8; i++)
{
if(crc_value & 0x0001)
{
crc_value >>= 1;
crc_value ^= 0xA001;
}
else
{
crc_value >>= 1;
}
}
}
return(crc_value);
}