Reducing Short-Cycle Oscillation; Dwell Functions: B6-01 To B6-04; S-Curve Characteristic Function: C2-01 To C2-04; Timing Chart For Dwell Functions - YASKAWA VARISPEED-616G5 Instruction Manual

Advanced Operation

7.5.2 Tuning Constants: C

7
7.5.2 Tuning Constants: C
Response

Reducing Short-cycle Oscillation

D
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 con-
trol), then either lower the proportional gain (P) or raise the PID primary delay time constant.
Response

Dwell Functions: b6-01 to b6-04

J
The dwell functions are used to temporarily hold the output frequency when starting or stopping a mo-
D
tor with a heavy load. This helps to prevent stalling.
User User
Constant Name
Number
Dwell frequency at
b6-01
start
b6-02
Dwell time at start
Dwell frequency at
b6-03
stop
b6-04 Dwell time at stop
The relation between these constants is shown in Figure 7.26.
D
Run command
Output
frequency
Fig 7.26

Timing Chart for Dwell Functions

S-curve Characteristic Function: C2-01 to C2-04

J
Using the S-curve characteristic function for acceleration and deceleration can reduce shock to the ma-
D
chinery when stopping and starting.
With the Inverter, S-curve characteristic times can be set respectively for beginning acceleration, end-
D
ing acceleration, beginning deceleration, and ending deceleration.
Before adjustment
After adjustment
Time
Before adjustment
After adjustment
Time
Change g
during during Setting Setting Unit Factory
Opera- Range
tion
0.0 to 400.0 Hz
×
0.0 to 10.0 s
×
0.0 to 400.0 Hz
×
0.0 to 10.0 s
×
ON
b6-01
b6-02
7 - 52
Valid Access Levels
Factory
Open
V/f V/f with
Setting
Loop
Control PG
Vector
0.0 A A A
A A A
0.0
A A A
0.0
0.0 A A A
OFF
b6-03
Time
b6-04
Flux
Vector
A
A
A
A