Q format and P.U value

Altair Forum User

Submitted by Mala Gowda on Tue, 01/08/2013 - 13:25

 

 

Hi:

What is the Q format followed in VisSim 8.0 version with TMS320F28062 piccolo controller selection. how do i know whether fixed point format is enabled or floating point and how to determine the P.u Values based on motor parameters like Ke=28mV/RPM and R=2mOhm.

Regards, MALA

Altair Forum User

Submitted by Anders89 on Wed, 01/09/2013 - 03:51.

 

All processors have fixed point capability. Some MCU's, like F2806x also have an FPU for hardware floating point. Standard VisSim blocks all support floating point. The VisSim fixed-point block set will simulate and generate code for fixed-point, which can run on any MCU.
If you look at the Wiki page on fixed-point arithmetic, VisSim uses the fxm.b notation in which m represents integer magnitude bits and n is word length. For example, fx4.16 describes a number with 4 magnitude bits and 12 fractional bits in a 16 bit word. Fixed-point blocks like fxConst or fxGain will give you the range of representable numbers for a given fixed-point format.