Individual Functions
6-
145
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
Con-
stant
Number
Name
Description
Setting
Range
Factory
Setting
Change
during
Opera-
tion
Control Methods
MEMO
BUS
Regis-
ter
Display
V/f
V/f
with
PG
Open
Loop
Vector
1
Flux
Vec-
tor
Open
Loop
Vector
2
b2-01
Zero-speed
level (DC injec-
tion braking
starting fre-
quency)
Used to set the frequency which
starts DC injection braking in
units of Hz when deceleration to
stop is selected.
When b2-01 is less than E1-09,
E1-09 becomes the DC injection
braking starting frequency.
(For flux vector control, zero-
speed control from B2-01)
0.0 to
10.0
0.5 Hz
No
A
A
A
A
A
189H
DCInj Start
Freq
b9-01
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
excitation level (b2-01), a posi-
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.
0 to
100
5
No
No
No
No
A
No
1DAH
Zero Servo
Gain
b9-02
Zero-servo
completion
width
Sets the output width of the P-
lock completion signal.
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
within the range (the zero-servo
po zero-servo completion
width.)
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.
0 to
16383
10
No
No
No
No
A
No
1DBH
Zero Servo
Count
