MODBUS Protocol 88
Objection code
04
20
21
22
23
24
Corresponding error
Invalid operation of slave machine
Too much read-write parameters
Reserve read-write, implicit parameter
Slave machine running forbids modifying data
Data modification is protected by password
Failure in read-write parameter
CRC CHECK:
CRC CHECK
Data length(Byte)
CRC Low
1
CRC High
1
CRC CHECK function is shown as below:
unsigned int crc_chk_value(unsigned char *data_value, unsigned char length)
{
unsigned int crc_value=0xFFFF;
int i;
while(length--)
{ crc_value^=*data_value++;
for(i=0;i<8;i++)
{ if(crc_value&0x0001)
crc_value=( crc_value>>1)^0xA001;
else
crc_value= crc_value>>1;
}
}
return(crc_value);
}
3. Definition of communication parameter address
Distribution of inverter parameter address
Register implication
Functional parameter(1)
Monitoring parameter
Operation command(2)
Frequency setting
Inverter status(3)
Fault message(4)
Register address space
High is the number of function code group, while low is mark
number of function code, e.g. F1.11, the register address is F10B.
High is 0xD0 and low is monitoring mark number, e.g. d-12, the
register address is D00C
0x1001
0x1002
0x2000
0x2001
E550 Series Universal Low-Power Inverter
