RMS Technologies R325P DRIVER - Manual (Page 29)

11. Appendix B: PF Value
For applications requiring ultimate smoothness of motion and extreme accuracy, the R325P driver can be
programmed via RS485 to change the Percent Fast Decay rate, or, the PF value.
The Percent Fast Decay default is 2, or a mixed mode of 48%.
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 = Slow Decay
1 = Mixed Mode 15%
2 = Mixed Mode 48%
3 = 100% Fast 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 or more. 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
RMS Technologies Page 29 Version 1.01
R325PE Single Axis Closed loop Driver/Indexer Manual 5/29/2013