Savch S2800 Series, Руководство пользователя

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K. ASCII analog Checking (LRC check)
Checking code (LRC check) is the summation from address to data content result.
For example, the checking code of above 1.6.2 communication information:
0x02+0x06+0x00+0x08+0x13+0x88=0xAB, then select=0x58 of supplement code of
2.
Here provides a simple function of LRC calculation summation for users' reference
(using C language programming).
Static unsigned char
LRC(auchMsg,usDataLen)
unsigned char *auchMsg;
{
unsigned char uchLRC=0;
while(usDataLen--)
=*+;
return((unsigned char)(~((char)uchLRC)));
}
L. Definition of Communication Data Address
It is the definition of communication data address, which is used to control inverter operation,
obtain the state information and relative function parameters.
(1) Using method of function code parameter address
Using numbers of function code as parameters to correspond to the register address, which has
to be converted to hexadecimal system. For example, the number of 05-05 is 62, the function
code address expressed by hexadecimal system is 003EH.
Ranges of high and low characters: high-bit character-00~01; low-bit character--00~FF.
Note: the group 13 is the parameter set in factory, whose parameters can't be read and modified
either. Some parameters can't be modified when the inverter is in operation state. Some always
can't be modified no matter what the state of inverter is. When modify the function code
parameter, pay attention to the setting range and unit of parameter and relative description.
In addition, the frequent storage of EEPROM will reduce its service life. For users, some function
codes don't need to be stored in communication mode. The application requirement can be meet
only through altering values in RAM. This function can be realized as long as changing the highest
bit of corresponding function code address from 0 to 1. For example, function code 00-06 isn't
stored into EEPROM, just alter the value in RAM and set the address as 8007. This address is
used only when write RAM, which can't be used as read function, otherwise, it is an unavailable
address.