Zero-Servo Function - YASKAWA Varispeed G7 Instruction Manual

Zero-servo Function

The zero-servo function holds the motor when the motor is stopped in what is call a zero-servo status. This
function can be used to stop the motor even with an external force acts on the motor or the analog reference
input is offset.
The zero-servo function is enabled when one of the multi-function inputs (H1-01 to H1-10) is set to 72 (zero-
servo command). If the zero-servo command is ON when the frequency (speed) reference falls below the zero-
speed level, a zero-servo status is implemented.
Related Constants
Name
Con-
stant
Display
Number
Zero-speed Used to set the frequency which
level (DC injec- starts DC injection braking in
tion braking units of Hz when deceleration to
starting fre- stop is selected.
b2-01 quency) When b2-01 is less than E1-09,
E1-09 becomes the DC injection
braking starting frequency.
DCInj Start
(For flux vector control, zero-
Freq
speed control from B2-01)
Zero-servo gain Adjust the strength of the zero-
servo lock.
Enabled when the zero-servo
command is set for a multi-func-
tion input. When the zero-servo
command has been input and the
frequency reference drop below
b9-01
Zero Servo
excitation level (b2-01), a posi-
Gain
tion control loop is created and
the motor stops. Increasing the
zero-servo gain in turn increases
the strength of the lock. Increas-
ing it by too much will cause
oscillation.
Zero-servo Sets the output width of the P-
completion lock completion signal.
width Enabled when the "zero-servo
completion (end)" is set for a
multi-function input. The zero-
servo completion signal is ON
when the current position is
b9-02 within the range (the zero-servo
position + zero-servo completion
Zero Servo
width.)
Count
Set the allowable position dis-
placement from the zero-servo
position to 4 times the pulse rate
of the PG (pulse generator,
encoder) in use.
Setting
Description
Range
0.0 to
0.5 Hz
10.0
0 to
100
0 to
16383
Control Methods
Change
Open
Factory during
V/f
Loop
Setting Opera-
V/f with
Vector
tion
PG
1
No A A A
5 No No No No
10 No No No No
Individual Functions
MEMO
Open
BUS
Flux
Loop
Regis-
Vec-
Vector
ter
tor
2
A A 189H
A No 1DAH
A No 1DBH
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