Alpha 6000 User Manual page 133

Chapter 5 Parameter Introductions
the running direction set by operation control command: that is to run forward
when the setting direction is forward rotation and run reversely when the setting
direction is reverse; and if the final frequency is negative, the running direction will
be in opposite to the direction set by operation control command: that is to run
forward when the setting direction is reverse rotation and run reversely when the
setting direction is forward rotation.
 When P7.04 is set to 1 in analog PID control, that is to enable PID direction
switching function, and the operation direction switch command is invalid during
running. The actual direction is determined by the setting direction at the start
moment and the PID frequency.
P7.05 PID proportional gain (Kp)
P7.06 PID integration time
P7.07 PID differential time
Note:

The proportional gain (Kp) is the parameter that decides the sensitivity of P action
in response to the deviation. The bigger the proportional gain Kp is, the more
sensitive the system acts and the faster the inverter responses. However, oscillation
may easily occur and regulation time extends. When Kp is too big, the system tends
to instability. When Kp is too small, the system will slow, and responses lag.
 Use integration time to decide the effect of integral action. The longer the
integration time, the slower the response, and the worse the ability of control
external disturbance variation. The smaller the integration time is, the stronger the
integral take effect. The smaller integration time can eliminate the steady state error
and improve control precision, fast response. However, oscillation may easily occur,
and the system stability decrease, if the integration time is too small.
 Differential time define the effect of differential action. The bigger differential time
can attenuate the oscillation caused by P action more quickly when deviations
occurs and short the regulation time. However, if differential time is too big,
oscillation may occur. If the differential time is small, the attenuation effect will be
small when deviations occur and the regulation time is longer. Only the right
differential time can reduce regulation time.
P7.08 PID delay time constant
Note:
 P7.08 set the output frequency delay time of PID.
P7.09 Residual margin
132
Range: 0.1~9.9【1.0】
Range: 0.00~100.0s【10.00s】
Range: 0.00~1.00s【0.00s】
Range: 0.00~25.00s【0.00s】
Range: 0.0~999.9【0.2】