RMS Technologies R101 DRIVER/INDEXER - Manual (Page 43)

RMS Technologies Page 43 Version 1.31
R101 Single Axis Driver/Indexer Manual 10/1/2007
14. Appendix B: PF Value
For applications requiring ultimate smoothness of motion and extreme accuracy, the
R3101 driver can be programmed via RS485 to change the Percent Fast Decay rate,
or, the PF value.
The Percent Fast Decay default is 1, or a mixed mode decay.
Mixed mode is a damping technique done to the driver IC. The following values
indicate the choices for Percent Fast Decay:
PF Values (0 through 3):
0 = Fast Decay
1 = Mixed Mode
2 = Slow Decay
Generally speaking, applications that run at slow speeds are recommended to use a
PF value of 1 or less. Fast speeds should use a PF value of 2. Since the best PF
value is dependent on the motor winding, loads, power supply voltage, and other
factors, it is best to use an oscilloscope and a current probe device to view the
current waveform and try different PF values. The following examples show good
and bad waveforms when choosing different PF values.
• PF value 1
• Slow speeds
• Good waveform