B9: Zero Servo - YASKAWA U1000 Technical Manual

5.2 b: Application
No.
b8-17
n b8-27: q-Axis Current Compensation Method when Output Voltage Is Limited
Sets a compensation method for the q-axis current when output voltage is limited.
There is normally no need to change this parameter from the default value.
No.
q-Axis Current Compensation Method when Output Voltage Is
b8-27
Setting 0: Output Voltage Limit Priority
Setting 1: q-Axis Current Priority
u

b9: Zero Servo

The Zero Servo function is a position loop that can be used to lock the motor at a certain position against external power to
the motor.
The drive will enter Zero Servo mode and maintain the current position when the following three conditions are true:
• The drive has an active Run command.
• A digital input programmed for Zero Servo (H1-oo = 72) is closed.
• The motor speed falls below b2-01 setting.
The drive accelerates when the input assigned to trigger the Zero Servo function is released and the Run command is still
present according to the speed reference.
When Zero Servo mode is active, the deviation between the rotor position and the zero position is displayed in monitor U6-22
(monitor value must be divided by 4 to get the deviation in actual encoder pulses).
A digital output programmed for "Zero Servo complete" (H2-oo = 33) is turned on when the rotor position is within the zero
position, plus or minus the Zero Servo completion width set to parameter b9-02.
Note: 1. The Run command must remain on when using the Zero Servo function. Zero Servo will not hold the load in place if the Run command
is switched off.
2. When the Zero Servo command has shut off, the Zero Servo Completion digital output also shuts off.
3. Avoid using Zero Servo to lock 100% load for long periods, as this can trigger a fault. If such loads need to be held in place for long
periods, either make sure the current is less than 50% of the drive rated current during Zero Servo, or use a larger capacity drive.
4. If the load rotates the motor when using CLV/PM, a dv4 fault may occur. To prevent this, either increase the Zero Servo gain (b9-01)
or increase the number of pulses set to F1-19 that are required to trigger dv4.
n b9-01: Zero Servo Gain
Adjusts the responsiveness of the Zero Servo position loop. Increase the value if the response is too slow and the deviation
from the zero position rises too high when load is applied. Decrease the value if vibrations occur during Zero Servo operation.
Note: Before adjusting the Zero Servo gain, make sure the ASR parameters (C5-oo) are set up properly and vibration or hunting does not occur
when running with a zero speed reference.
220
Name
Energy Saving Parameter (Kt) for PM Motors
Name
Limited
Frequency
Reference
b2-01
Closed
Run command
Zero Servo
input
Motor Speed
Follows active
decel ramp
b2-01
Zero Servo
operation
Figure 5.30 Zero Servo Operation
Closed
Follows active
accel ramp
ON
YASKAWA ELECTRIC SIEP C710636 04D U1000 Industrial MATRIX Drive Technical Manual
Setting Range
0.00 to 3.00
Setting Range
0, 1
Default
1.00
Default
0