Omron SYSDRIVE 3G3RV, User Manual

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6
-122
Suppressing Short Cycle Vibration
If
vibration occurs when the vibration cycle is short, and the cycle is almost identical to the derivative time (D)
set
value, the differential operation is too strong. Shorten the derivative time (D) to suppress the vibration.
If
vibration continues even when the derivative time (D) is set to 0.00 (D control disabled), reduce the propor-
tional
gain (P), or increase the PID primary delay time constant.
n
Setting Precautions
• In
PID control, the b5-04 parameter is used to prevent the calculated integral control value from exceeding
a
specified amount. When the load varies rapidly, Inverter response is delayed, and the machine may be
damaged
or the motor may stall. In this case, reduce the set value to speed up Inverter response.
• The
b5-06 parameter is used to prevent the arithmetic operation following the PID control calculation from
exceeding
a specified amount. Set taking the maximum output frequency to be 100%.
•
The
b5-07 parameter is used to adjust PID control offset. Set in increments of 0.1%, taking the maximum
output
frequency to be 100%.
•
Set
the low pass filter time constant for the PID control output in b5-08. Enable this parameter to prevent
machinery
resonance from occurring when machinery adhesive abrasion is great, or rigidity is poor. In this
case,
set the constant to be greater than the resonance frequency cycle. Increase this time constant to
reduce
Inverter responsiveness.
• Using
b5-09, you can invert the PID output polarity. Consequently, if you increase the PID target value,
you
can apply this parameter to applications to lower the Inverter output frequency.
• Using
b5-10, you can apply gain to the PID control output. Enable this parameter to adjust the amount of
compensation
if adding PID control output to the frequency reference as compensation.
• When
the PID control output is negative, the output direction can be reversed by the parameter b5-11.
However,
PID control output is limited to 0 when b1-04 (Prohibition of reverse operation) is set to 1
(enabled).
•
With
the Inverter, by setting an independent acceleration/deceleration time in parameter b5-17, you can
increase
or decrease the PID target value using the acceleration/deceleration time. The acceleration/
deceleration
function (C1 parameters) used normally, however, is allocated after PID control, so depending
on
the settings, resonance with PID control and hunting in the machinery may occur. If this happens,
reduce
C1 parameters until hunting does not occur, and maintain the acceleration/deceleration time using
b5-17.
Also, you can disable the set value in b5-17 from the external terminals during operation using
multi-function
input set value 34 (PID soft starter).
Response
Before adjustment
After adjustment
Time