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5.2 b: Application
YASKAWA ELECTRIC
SIEP C710636 02B YASKAWA U1000 Technical Manual
211
5
Setting 1: Reverse Enabled
Negative PID output will cause the drive to run in the opposite direction.
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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.
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
OFF
OFF
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