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Menu 2
Unidrive SP Advanced User Guide 45
Issue Number: 10 www.controltechniques.com
2: Standard ramp with motor voltage boost
This mode is the same as normal standard ramp mode except that the motor voltage is boosted by 20%. This increases the losses in the motor giving
faster deceleration.
Setting this parameter enables the S ramp function. S ramp is disabled during deceleration when the standard ramp voltage controller is active. When
the motor is accelerated again after decelerating in standard ramp the acceleration ramp used by the S ramp function is reset to zero.
This parameter defines the maximum rate of change of acceleration/deceleration. If the S ramp is disabled (Pr 2.06 = 0) a linear ramp is used and the
time in seconds taken for the ramp output to change by frequency ( Δ f*) or speed (Δ w*) is given by:
Frequency (Open-loop mode)
T
Ramp =
Δf* x A / 100
where A is the selected ramp rate in s / 100Hz
Speed (Closed-loop vector and servo)
T
Ramp =
Δw* x A / 1000
Where A is the selected ramp rate in s / 1000rpm
If the S ramp is enabled (Pr 2.06 = 1) then the ramp time is extended as shown in the diagram below.
2.06 S ramp enable
Drive modes Open-loop, Closed-loop vector, Servo
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
111
Default Open-loop, Closed-loop vector, Servo 0
Update rate 4ms read
2.07 S ramp acceleration limit
Drive modes Open-loop, Closed-loop vector, Servo
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
1111
Closed-loop vector and Servo DP = 3
Range
Open-loop
Closed-loop vector and servo
0.0 to 300.0 s
2
/100Hz
0.000 to 100.000 s
2
/1,000rpm
Default
Open-loop
Closed-loop vector
Servo
3.1
1.500
0.030
Update rate Background read
DC Bus voltage
Motor Speed
Programmed
deceleration
rate
t
Controller
operational