Rockwell Automation 20P PowerFlex Digital DC Drive - Manual (Page 292)

292 Rockwell Automation Publication 20P-UM001I-EN-P - February 2013
Appendix C Application Notes
Speed Zero Function
The Speed Zero Logic determines the behavior of the drive when the motor is at
zero speed. See the Speed Adaptive and Speed Zero Logic block diagram on page
325 .
Configuring the Speed Zero Logic
It is possible to avoid drive creep when the motor is at zero speed by disabling the
Integral section of the Speed regulator. By default, the output of the Integral
portion of the Speed regulator is disabled (Par 123 [Spd Zero I En] = 0
“Disabled”).
Disable the output of the P gain of the Speed regulator by setting Par 126 [Spd
Zero P Gain] to one of the following settings:
• If the speed reference is above the value set in Par 106 [Ref Zero Level]: Set
Par 124 [Spd Ref Zero En] = 1 “Enabled”
• If the speed reference and/or the reaction are above the value set in Par 106
[Ref Zero Level], set Par 124 [Spd Ref Zero En] = 0 “Disabled”
Par 124 [Spd Ref Zero En] is active only when Par 125 [Spd Zero P En] = 1
“Enabled”.
P118
Speed Reg In
P122
Spd Feedback
P104
At Speed Error
P105
At Speed Delay
0 t
At Speed
P394
[Digital Outx Sel]
= 3 “At Speed”
IMPORTANT If the speed regulator is disabled, the motor cannot receive a load when it is
stopped. Therefore this function is not suitable for all applications!