1: Standard ramp
The standard ramp controller (shown in the diagram below) is only enabled when the Pre-ramp Reference (01.003) is closer to zero than
the Post Ramp Reference (02.001), i.e. during deceleration. As the motor slows down power is fed into the d.c. bus of the drive which causes the
voltage to rise. When the voltage reaches the level defined by the Standard Ramp Voltage (02.008) the d.c. bus voltage controller becomes active and
provides a torque producing current reference. This system regulates the d.c. bus voltage to hold it at the level defined by the Standard Ramp Voltage
(02.008). Generally as the motor slows down the deceleration needs to be increased to provide enough power to maintain the d.c. bus level. The
frequency or speed is not allowed to fall faster than the final deceleration rate, and so a point is reached where the controller de-activates itself, and the
final deceleration rate is used until the motor reaches standstill. If at any point the Pre-ramp Reference (01.003) is equal to or further from zero than the
Post Ramp Reference (02.001), i.e. not decelerating, the d.c. bus voltage controller is de-activated.
2: Standard ramp with motor voltage boost
Standard ramp with motor voltage boost is the same as standard ramp mode except that the motor voltage is boosted by 20% to increase the motor
losses and reduce the deceleration time.
If the Standard Ramp Voltage (02.008) is set to a level that is below the nominal d.c. bus voltage level the motor will coast during deceleration because
the torque producing current reference is limited to prevent the motor from accelerating.
Parameter 02.006 S Ramp Enable
Short description Set to 1 to enable the use of S ramps
Mode Open‑Loop
Minimum 0 Maximum 1
Default 0 Units
Type 1 Bit User Save Update Rate 4ms read
Display Format Standard Decimal Places 0
Coding RW
If S Ramp Enable (02.006) = 0 linear ramps are used, but if S Ramp Enable (02.006) = 1 an acceleration limit is applied to give S ramps. See
Maximum Rate Of Change Of Acceleration (02.007) for more details of S ramps.
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