B9: Zero Servo - YASKAWA GA700 Series Technical Manual

12.3 b: Application
A - Drive
B - MFDO Terminal
■
b8-51: Standby Mode Wait Time
No.
Name
(Hex.)
b8-51 Standby Mode Wait Time
(0B01)
◆

b9: Zero Servo

Zero Servo is a position control function that stops and holds the motor shaft. The drive safeties the stopped motor
and an external force will not move the motor.
When you enable the Zero Servo function, the drive will save the home position. The drive can correct the motor
position and put the motor into the home position when the load rotates the motor.
To enable Zero Servo, set H1-xx = 72 [MFDI Function Selection = Zero Servo]. The drive starts Zero Servo when
the MFDI terminal set for Zero Servo [H1-xx = 72] activates and the motor speed decreases to less than the value
set in b2-01 [DC Injection/Zero SpeedThreshold]. The drive stops and holds the motor in the Zero Servo start
position. When Zero Servo is enabled, the drive will hold the motor in position when the frequency reference
increases to more than the value set in b2-01. When Zero Servo is enabled, the drive will hold the motor in
position when the frequency reference increases to more than the value set in b2-01.
Note:
Zero Servo is available when A1-02 = 3, 7 [Control Method Selection = Closed Loop Vector, PM Closed Loop Vector].
Monitor U6-22 [ZeroServoPulse Move] shows the difference between the position of the motor shaft and the Zero
Servo start position when Zero Servo is enabled. To find the difference, divide the number of pulses shown in U6-
22 by 4.
When the position of the motor shaft is in the range of "Zero Servo start position ± b9-02 [Zero Servo Completion
Window]", the drive will activate an MFDO set for Zero Servo Complete [H2-xx = 33].
NOTICE: Do not let the Zero Servo function hold 100% load for long periods of time. When the application must use Zero Servo
to hold 100% load for long periods, operate in less than 50% of the drive rated output current or use a larger capacity drive. If
Zero Servo holds the load for too long in 50% or more of the drive rated output current, it will cause damage to the drive.
690
V/f CL-V/f OLV CLV AOLV
Sets the delay time before turning off the electromagnetic contactor after the drive stops.
Figure 12.44 Zero Servo Time Chart
C - External 24 V power supply
Description
OLV/PM AOLV/PM CLV/PM EZOLV OLV/PM
YASKAWA SIEPC71061705H GA700 Series Technical Manual
Default
(Range)
600 s
(0 - 6000 s)