6-104
6
îš„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, the Inverter response is delayed, and the machine might
get 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 output value of the PID control calculation from exceeding a
specified amount. The value is set taking the maximum output frequency as 100%.
• The b5-07 parameter is used to adjust PID control offset. The value is set in increments of 0.1%, taking the
maximum output frequency to be 100%.
• Set the filter time constant for the PID control output in b5-08. Enable this parameter to prevent machinery
resonance when machinery friction is high, or rigidity is poor. In this case, set the parameter to be higher
than the resonance frequency cycle duration. Increase this time constant to reduce Inverter responsiveness.
• Using b5-09, the PID output polarity can be inverted. If now the PID feedback value increases the output
frequency will be increased. This function is usable e.g. for vacuum pumps.
• Using b5-10, you can apply a 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 (b5-01 = 3/4).
• When PID control output is negative, you can use parameter b5-11 to determine what happens to the
inverter output. When b1-04 (Prohibition of Reverse Operation) is set to 1 (enabled), however, the PID
output is limited to 0.
• Using the b5-17 parameter the PID target value can be raised or lowered with an accel./decel. ramp func-
tion (PID soft starter).
The normally used accel./decel. function (C1- parameters) is allocated after PID control so that,
depending on the settings, resonance with the PID control and hunting in the machinery may occur. Using
b5-17 this behavior can be prevented.
The PID soft starter function can also be disabled or enabled using a multifunction digital input (H1-
has to be set to 34).
To Next Page
Loading...
Need help?
General