JAJSSE7 November 2023 DRV8214
PRODUCTION DATA
Denoted by KMC_SCALE, this is a scaling factor for the parameter KMC. KMC is represented by the following equation:
Where, KV is the motor back emf constant and NR is the number of ripples per revolution. NR is calculated by taking the LCM (Least Common Multiple) of the number of brushes, NB, and the number of commutators, NC:
Please note that LCM can be easily calculated by using any online LCM calculator.
Tuning KMC appropriately is critical for the ripple counting algorithm to perform accurately. Scaling is done because the value of motor back emf constant is generally small. Scaling allows integer values to be written on to registers.
Bit | Value of KMC_SCALE |
---|---|
00b | 24 x 28 |
01b | 24 x 29 |
10b | 24 x 212 |
11b | 24 x 213 |