V&T Technologies Co., Ltd.
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Appendix A Modbus Communication Protocol
137
0xF001
PE.00 password authentication for the display and hidden areas of the specially authenticated
function codes of the inverter, and it will be closed automatically if no operation is performed
within five minutes.
0xF002
A0.00 password authentication for the display and hidden attributes customized areas of the
function codes of the inverter, and it will be closed automatically if no operation is performed
within five minutes.
Register for function code characteristics of the inverter
Attached Table-5
Register
address
Meaning
Range
Read (R) and Write (W)
0xF080
Relative address of the
function code
See Attached Table-1
R/W
0xF081
Current value
0 ~ 65535
R/W
0xF082
Upper Limit
0 ~ 65535
R
0xF083
Lower Limit
0 ~ 65535
R
0xF084
Factory default value of the
function code
0 ~ 65535
R
It can write the function code No. into 0xF080 by reading and writing multiple register commands 0x17
firstly and then read several attributes of this function code.
6. CRC16 Function
unsigned int crc16(unsigned char *data,unsigned char length)
{
int i,crc_result=0xffff;
while(length--)
{
crc_result^=*data++;
for(i=0; i<8; i++)
{
if(crc_result&0x01)
crc_result=(crc_result>>1) ^0xa001;
else
crc_result=crc_result>>1;
}
}
return (crc_result=((crc_result&0xff) <<8) |(crc_result>>8) ) ; //Exchange CRC16 check sum and bytes at
higher and lower orders
}
7. Case Study of Modbus Communication Control
Start No.1 inverter to perform forward rotation, and set the rotation velocity to 50.00Hz (indicating 5,000 internally) as
per the following commands:
Address
Function
code
Register
Address
Number
Bytes
Register
Contents
Check Sum
Request
0x01
0x10
0x8000
0x0002
0x04
0x0001,0x1388
0xCEFF
Response
0x01
0x10
0x8000
0x0004
None
None
0xE80A
