Part Number:DRV10983
Hi,
I am using the DRV10983 to drive a motor. I did some RPM measurements (using different loads and speeds) with the DRV10983 EVM GUI and a separate laser RPM measurement system.
The Motor Speed (RPM) value displayed in the GUI is closest to the laser measurement. Motor Speed in Hz and Electrical Period converted to RPM are both different from the displayed Motor Speed RPM.
Here are my measurements, I use an 8 pole motor, and used the formula RPM=f(Hz)*(2/nr poles)*60 or RPM=f(Hz)*120/8:
Motor Speed (RPM)
244,18
644,053
1390,18
283,447
652,458
1307,76
267,094
649,351
1218,52
Motor Speed (Hz) Conv2 RPM
17,1 256,5
45,2 678
96,3 1444,5
19,4 291
45,5 682,5
91 1365
18,5 277,5
45,2 678
85,1 1276,5
Eelectrical Period (us) Conv2 RPM
61420 244,2201237
23160 647,6683938
10780 1391,465677
52830 283,9295855
22940 653,8796861
11420 1313,485114
54920 273,1245448
23150 647,9481641
12260 1223,491028
Why is there a difference between the Motor Speed (RPM) and the Motors Speed (Hz) and Electrical Period (us) when converted to RPM? From what and how do you compute the Motor Speed (RPM) value in the DRV10983 EVM GUI?
I will have to read the motor’s RPM over I2C and use it in a control algorithm. For that I can either use the value from the Motor Speed 1&2 or Motor Period 1&2 registers. Which register would you advise to use, which one would be more accurate?
Thank you.
Best regards,
Vlad