10-12-2007 01:02 AM
Hi, Walker, Jim,
Your request for document is reasonable. Unfortunately, we don't have a comprehensive tutorial on Fixed-Point itself yet. Basically you configure fixed-point data type according to the range and precision of the value you want to represent. The range determines the signed/unsigned and integer word length. The precision determines the fractional word length:
For a signed FXP, the value range is: [-2^(iwl-1), 2^(iwl-1)-2^(-fwl)]
For an unsigned FXP, the value range is [0, 2^iwl-2^(-fwl)]
where iwl is integer word length, and fwl is the word length of the fracational part. iwl+fwl is the word length. So if you are aware of the range and precision of a parameter, you can infer an appropriate FXP format according to the formula above.
The integer word length is actually a logic concept, which denotes a scale factor, thus can be negative. For example, for an 8-bit unsigned FXP number "11001001" (201 in decimal), the real value it represents is 201/2^(8-iwl).
Hope this helpful.
10-12-2007 07:53 AM
10-12-2007 08:02 AM
For fixed-point constants you can turn on "Adapt to entered data" from the popup menu. This will pick the best fixed-point configuration based on the number you type in.
For front panel indicators you can turn on "Adapt to source" from the popup menu. The indicator will change adapt to whatever numeric type is wired to it.
10-14-2007 08:59 AM
10-15-2007 09:42 AM
11-09-2007 09:49 AM - edited 11-09-2007 09:50 AM
02-25-2008 07:51 AM
nice library! but what is the difference between the "fixed point add" function and the native add function from Labview ? the native add function can also handle fixed-point.
02-25-2008 08:14 PM - edited 02-25-2008 08:17 PM
04-23-2008 12:00 PM
04-23-2008 09:17 PM