从手册上提供的说明可以得到部分参说的寄存器地址，但是很有限，不能够满足需求，现在手册上有一些不明白的地方如下：
Parameter 40,090 1 0-999 r/w
see page 85
Primary Index 40,091 1 0 - 9 r/w
Secondary Index 40,092 1 0 - 9 r/w
Format Word 40,093 1 bit mapped r/w
Read Value (word 1) 40,094 2 32 bits r
Write Value (word 1) 40,096 2 32 bits r/w
以上几个参数有什么用，看的时候一知半解，是不是可以用他们去间接的读或写BW500其他的一些参数。后面还有Format Word的具体格式，该字是不是一个控制字，控制40094里面的值的格式？
Reading Parameters
To read parameters through Modbus follow these steps:
1. Send the parameter, its primary index, and its secondary index (usually 0) and
format to registers 40,090, to 40,093.
2. Wait until you can read the above values from the registers (40,090 to 40,093).
3. Read the value from registers 40,094 and 40,095.
Writing Parameters
To set parameters through Modbus follow these steps:
1. Send the parameter, its primary index, and its secondary index (usually 0) to
registers 40,090, 40,091, and 40,092.
2. Write the value to registers 40,096 and 40,097
3. Write the desired format word to register 40.093 to enable the BW 500 to interpret
the value correctly.是什么意思？
The value sent to the BW 500 is 0001001000000000 binary or 4608 decimal. The value
4608 is sent as an integer to register 40,093 to format the output words 40,094 and 40,095
accordingly.
If the numeric data type is set for integer and the value contains decimal places they are
ignored. In this situation use the decimal offset to ensure that you have an integer value
and then write your code to recognize and handle the decimal offset. Bits 9 to 11 indicate
the number of place by which the decimal is to be shifted. Bit 12 indicates the direction by
which the decimal point is shifted, left or right. For example, if the decimal offset (value of
bits 9 to 11) is ‘2’ and the shift (value of bit 12 is ‘0’), then the decimal point is shifted two
places to the right.
怎么解释？
望高手指教！！！！急盼