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Specification of high-performance vector convertor
During producing process of CRC, each 8-bit byte is XOR with register contents separately. Finally, it
moves to the direction of least significant bit, and most significant bit is filled with 0. LSB is extracted for
detection. If LSB is 1, register is XOR with preset value. If LSB is 0, no action. Repeat the whole process
for 8 times. After last bit (8
final value in register is CRC value after all bytes in message are executed.
When adding CRC to message, add low byte firstly and then high byte. Simple function of CRC is as
below:
unsigned int crc_chk_value（unsigned char *data_value, unsigned char length）{
^0xa001;
}
Address definition of communication parameter
This part is communication content used for controlling operation of frequency convertor, setting
state and related parameters of frequency convertor.
Read-write function code parameter (some function codes can't be modified, but are simply used or
monitored by manufacturer).
Marking rules of function code parameter address:
Express rules with group No. and marking No. of function code being parameter address:
High byte: P0~PF (P group), A0~AF (A group), 70~7F (U group); low byte: 00~FF
E.g.: P3-12, address is expressed as P30C;
Note: PF group: neither read nor modify parameters;
U group: only read but not modify parameters.
When the frequency convertor is in running status, some parameters can't be modified. Some
parameters can't be modified no matter what is the status of frequency convertor. When modifying the
function code parameters, range, unit and related descriptions of parameters should be also noticed.
Besides, as EEPROM is frequently stored, it will reduce lifespan of EEPROM. Therefore, under
communication mode, some function codes don't have to be stored, and only modify the value in RAM.
bit) finishes, next 8-bit byte is XOR with current value of register alone. The
th
unsigned int crc_value=0xFFFF;
int i;
while（length--）
crc_value^=*data_value++;
for（i=0;i<8;i++）
{
}
}
return（crc_value）;
if（crc_value&0x0001）
crc_value= （ crc_value>> 1）
}
crc_value=crc_value>>1;
else
{
}
- 172 -
Appendix
{
{
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