B9: Zero Servo - YASKAWA A1000 Technical Manual


b8-17: Energy Saving Parameter (Kt) for PM Motors
Coefficient to adjust torque linearity.
This parameter rarely needs to be changed.
When E5-01 (Motor Code Selection (for PM Motors)) is set to 1 or 2, the automatically calculated value
will be set. This set value cannot be changed. If oscillation occurs when Energy Saving is enabled (b8-01 = 1), then check
the value displayed in monitor U5-22. If the value displayed differs from the Kt value written on the motor nameplate,
then set b8-17 accordingly.
No.
b8-17
<1> The setting range of the drives is 0.00 to 2.00 for software versions S1018 and earlier.
<2> The setting range is 0.00 to 2.00 for models CIMR-A4A0930 to 4A1200.

b8-27: q-Axis Current Compensation Method when Output Voltage is Limited
There is normally no need to change this parameter from the default value. Sets a compensation method for the q-Axis
current when output voltage is limited.
Note: This parameter is not available in models CIMR-A4A0930 and 4A1200.
No.
b8-27
Setting 0: Output Voltage Limit Priority
Setting 1: q-Axis Current Priority
 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.
It must be activated using a digital input set for H1- = 72. The drive will enter Zero Servo mode and maintain the
current position when the input closes and motor speed falls below the level set in b2-01. Even if the motor speed
exceeds the level set in parameter b2-01 in Zero Servo mode, the drive will continue to maintain the current position. 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.
Figure 5.32
Decrease the speed
When Zero Servo 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- = 33) is turned on when the rotor position is within the
zero position, plus or minus the Zero Servo completion width set in parameter b9-02.
Note: 1. The Run command must remain on when using the Zero Servo function. If the Run command is switched off, then Zero Servo will no
longer be able to hold the load in place.
2. When the Zero Servo command has shut off, the Zero Servo Completion digital output width 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.
YASKAWA ELECTRIC SIEP C710616 27G YASKAWA AC Drive A1000 Technical Manual
Name
Energy Saving Parameter (Kt) for PM Motors
Name
q-Axis Current Compensation Method
when Output Voltage is Limited
Run command
Zero Servo command
Motor Speed
b2-01
DC Injection Braking
reference
start frequency
Figure 5.32 Zero Servo Operation
0.00 to 3.00
ON
ON
Zero Servo
Operation
5.2 b: Application
Setting Range Default
<1> <2>
Setting Range Default
0, 1
OFF
OFF
1.00
0
5
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