Yaskawa G5HHP Drive - Manual (Page 213)

7.5 Common Functions
7 - 49
D
Reducing Long-cycle Oscillation
If oscillation occurs with a longer cycle than the integral time (I) setting, it means that integral operation
is strong. The oscillation will be reduced as the integral time (I) is lengthened.
After adjustment
Before adjustment Response
Time
D
Reducing Short-cycle Oscillation
If the oscillation cycle is short and oscillation occurs with a cycle approximately the same as the deriva-
tive time (D) setting, it means that the derivative operation is strong. The oscillation will be reduced as
the derivative time (D) is shortened.
If oscillation cannot be reduced even by setting the derivative time (D) to “0.00” (no derivative control),
then either lower the proportional gain (P) or raise the PID primary delay time constant.
After adjustment
Before adjustment
Response
Time
J
Dwell Functions: b6-01 to b6-04
D
The dwell functions are used to temporarily hold the output frequency when starting or stopping a motor
with a heavy load. This helps to prevent stalling.
User
Change
during Setting Factory
Valid Access Levels
User
Constant
Number
Name
g
during
Opera-
tion
Setting
Range
Unit Factory
Setting V/f
Control
V/f with
PG
Open
Loop
Vector
Flux
Vector
b6-01
Dwell frequency at
start
x 0.0 to 150.0 Hz 0.0 A A A A
b6-02 Dwell time at start x 0.0 to 10.0 s 0.0 A A A A
b6-03
Dwell frequency at
stop
x 0.0 to 150.0 Hz 0.0 A A A A
b6-04 Dwell time at stop x 0.0 to 10.0 s 0.0 A A A A
D
The relation between these constants is shown in Figure 7.23.
Output
frequency
b6-02
b6-01
b6-04
Time
b6-03
Run command OFF ON
Fig 7.23 Timing Chart for Dwell Functions
7