5.2 b: Application
YASKAWA ELECTRIC
SIEP C710636 02B YASKAWA U1000 Technical Manual 211
Setting 1: Reverse Enabled
Negative PID output will cause the drive to run in the opposite direction.
■
Fine-Tuning PID
Once PID control parameters have been set, fine-tuning may be required. Follow the directions below.
Table 5.12 PID Fine Tuning
◆ b6: Dwell Function
The Dwell function is used to temporarily hold the frequency reference at a predefined value for a set time, then continue
accelerating or decelerating.
If used with induction motors, the Dwell function can help prevent speed loss when starting and stopping a heavy load. If
running a PM motor in V/f control, the pause in acceleration allows the PM motor rotor to align with the stator field of
the motor, thus reducing the starting current.
Figure 5.27 shows how the Dwell function works.
Note: Using the Dwell function requires that the stopping method for the drive be set to “Ramp to stop” (b1-03 = 0).
Figure 5.27
Figure 5.27 Dwell Function at Start and Stop
Goal Tuning Procedure Result
Overshoot must be suppressed
• Reduce the derivative time (b5-05)
• Increase the integral time (b5-03)
Quickly achieve stability, and some
overshoot is permissible
• Decrease the integral time (b5-03)
• Increase the derivative time (b5-05)
Suppress long cycle oscillations (longer than
the integral time setting)
Increase the integral time (b5-03)
Suppress short cycle oscillations
• If oscillation cycle time is close to the derivative
time, the derivative part is likely having too much
influence. Reduce the derivative time (b5-05).
• If the derivative time is set to 0.00 s and
oscillations are still a problem, try reducing the
proportional gain (b5-02) or try increasing the
PID primary delay time (b5-08)
Response
Before adjustment
After adjustment
Time
Response
Before adjustment
After adjustment
Time
Response
Before adjustment
After adjustment
Time
Response
After adjustment
Before adjustment
Time
b6-01
b6-03
b6-02 b6-04
Run Command
Output Frequency
ON
OFFOFF
SIEP_C710636_02B_1_0.book 211 ページ ２０１５年１１月２５日 水曜日 午後４時５６分
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