Delta VFD-L-I Series, User Manual

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Chapter 4 Parameters
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VFD-L-I Series
4-56 Revision July 2009, SW V1.1
For example, reading 2 words from address 2102H of the AC drive with address 01H.
ADR 01H
CMD 03H
21H Starting address
02H
00H
Number of data
(count by word)
02H
CRC CHK Low 6FH
CRC CHK High F7H
The following is an example of CRC generation using C language. The function takes two
arguments:
Unsigned char* data
Å
a pointer to the message buffer
Unsigned char length
Å
the quantity of bytes in the message buffer
The function returns the CRC value as a type of unsigned integer.
Unsigned int crc_chk(unsigned char* data, unsigned char length){
int j;
unsigned int reg_crc=0xFFFF;
while(length--){
reg_crc ^= *data++;
for(j=0;j<8;j++){
if(reg_crc & 0x01){ /* LSB(b0)=1 */
reg_crc=(reg_crc>>1) ^ 0xA001;
}else{
reg_crc=reg_crc >>1;
}
}
}
return reg_crc;
}
3.5 Address list
The contents of available addresses are shown as below:
Content Address Functions
AC drive
Parameters
ggnnH gg means parameter group, nn means parameter number, for
example, the address of Pr.04-01 is 0401H. Referencing to
chapter 5 for the function of each parameter. When reading
parameter by command code 03H, only one parameter can be
read at one time.