
Adjustment Suggestions
4-
21
Procedure for Increasing the Speed Response
•
Do not change the Torque Compensation Gain (C4-01) from its default setting of 1.00 when using open-
loop vector 1 control.
•
If speeds are inaccurate during regeneration in open-loop vector 1 control, enable Slip Compensation Dur-
ing Regeneration (C3-04 = 1).
•
Use slip compensation to improve speed control during V/f control (A1-02 = 0).
Set the Motor Rated Current (E2-01), Motor Rated Slip (E2-02), and Motor No-load Current (E2-03), and
then adjust the Slip Compensation Gain (C3-01) to between 0.5 and 1.5. The default setting for V/f control
is C3-01 = 0.0 (slip compensation disabled).
•
To improve speed response and stability in V/f control with a PG (A1-02 = 1), set the ASR constants (C5-
01 to C5-05) to between 0.5 and 1.5 times the default. (It is not normally necessary to adjust this setting.)
ASR for V/f control with a PG will only control the output frequency; a high gain, such as is possible for
open-loop vector 2 control or flux vector control, cannot be set.
The following user constants will also indirectly affect the control system.
Table 4.5 Constants Indirectly Affecting Control and Applications
Name (Constant Number)
Application
Dwell function (b6-01 to b6-04)
Used for heavy loads or large machine backlashes.
Droop function (b7-01 to b7-02)
Used to soften the torque or to balance the load between two motors. Can
be used when the control method (A1-02) is set to 3 or 4.
Acceleration/deceleration times
(C1-01 to C1-11)
Adjust torque during acceleration and deceleration.
S-curve characteristics (C2-01 to C2-04)
Used to prevent shock when completing acceleration.
Jump frequencies (d3-01 to d3-04)
Used to avoid resonance points during operation.
Analog input filter time constant (H3-12)
Used to prevent fluctuations in analog input signals caused by noise.
Stall prevention
(L3-01 to L3-06, L3-11, L3-12)
Used to prevent overvoltage errors and motor stalling for heavy loads or
rapid acceleration/deceleration. Stall prevention is enabled by default and
the setting does not normally need to be changed. When using a braking
resistor, however, disable stall prevention during deceleration by setting
L3-04 to 0.
Increase the speed response.
C5-01
≥
30.0
No
Yes
C5-06
≤
0.01
No
Yes
Is the speed response to be
increased for low-speed
operation or high-speed
operation?
Speed
≥
N4-11
Speed
<
N4-11
Reduce the setting for the integral time of
speed estimator (N4-07). (Typically,
reduce in intervals of 0.005.)
Increase the setting for the ASR proportional gain (C5-01).
(Typically, increase in intervals of 5.)
Reduce the setting for the ASR primary delay time (C5-06).
(Typically, reduce in intervals of 0.01.)
Increase the setting for the high-speed proportional gain of
speed estimator (N4-10). (Typically, increase in intervals
of 5.)