Omron M1 Series User Manual page 434

6 Vector Control and Applied Functions
Speed Detection Filter (d02/A44/b44/r44)
This parameter is for setting the time constant of the primary lag filter with respect to the speed detec-
tion value. This is a filter for feedback. Set it when the mechanical system vibrates.
Adjust this parameter, for example, when ripple (vibration component) is carried on the speed detec-
tion signal as a result of the control target (mechanical system) such as belt deflection, and hunting
caused by that vibration component prevents gain, etc. of the PI controller from being sufficiently in-
creased (response is slow). Also, set this parameter when there are few pulses from the encoder
which results in a speed that causes vibration.
When the filter time constant is increased, the speed detection value is stabilized, and the gain of the
PI controller can be increased even if ripple is carried on the speed detection signal. Note, however,
that as speed detection itself is delayed, speed response slows down, overshooting increases and
sometimes results in hunting.
P (Gain) (d03/A45/b45/r45), I (Integral Time) (d04/A46/b46/r46)
These parameters are for setting the gain and integral time of the speed controller (ASR).
By setting d04 = 999, the integral operation can be disabled.
• P (gain)
Definition of P gain = 1.0 is a torque command of 100% (100% torque output at each capacity) when
the speed deviation (speed command - actual speed) is 100% (equivalent to the maximum speed
setting).
Adjust the P gain according to the moment of inertia of the machine connected to the motor shaft.
When the moment of inertia increases, P gain also must be increased to ensure the same response.
When P gain is increases, control response becomes faster, however, the motor speed sometimes
overshoots and the motor hunts. Also, machine resonance and excessive noise amplitude causes
the machine or motor to generate abnormal noise.
If this happens, the resonance amplitude can be decreased by lowering P gain. However, exces-
sively decreasing P gain causes control response to slow down, low-frequency speed fluctuations to
occur, and stabilization of the motor speed to take longer.
• I (integral time)
When the integral time is set to a small value, response is fast as the correction time for deviation is
short. To allow overshooting to enable the target speed to be reached quickly, decrease the set val-
ue, and when overshooting cannot be allowed, increase the set value.
In cases where machine resonance occurs and abnormal machine noise is emitted from the motor
and gears, the resonance point can be moved to the low frequency side to suppress resonance in
the high frequency region by increasing the integral time.
FF (Gain) (d05/A47/b47/r47)
This parameter performs feedforward control for adding the torque that is determined from the amount
of change in the speed command directly to the torque command.
PI control of the speed controller is feedback control whereby corrective action (following the speed
command) is performed according to the result (actual speed value) of the control target. Accordingly,
with this control, correction also is effective on external disturbances that cannot be measured and
causes that cannot be directly measured such as the uncertainty of control target characteristics.
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M1 Series Standard Type User's Manual (I669)