ABB ACS255 User Manual page 49

50
Parameters in the Long parameter mode
Index Name/Selection
2206 2nd DECELERATION RAMP
TIME
0.00...240.0 s
2210 FIELDBUS RAMP CONTROL
0 : Disabled
1 : Enabled
23 VECTOR CONTROL MODE
OPTIMISE
2301 VECTOR SPEED
CONTROLLER
PROPORTIONAL GAIN
0.1...400.0 %
2302 VECTOR SPEED
CONTROLLER INTEGRAL
TIME CONSTANT
0.000...2.000 s
2303 VECTOR SPEED CONTROL
D GAIN
0.0...400.0 %
2305 SYSTEM INERTIA
CONSTANT
0...600
25 CRITICAL SPEEDS
2500 SKIP FREQUENCY BAND
WIDTH
0.0...2008
2501 SKIP FREQUENCY CENTRE
POINT
2007...2008
Description
This parameter allows an alternative deceleration ramp down time to be programmed into
the ACS255, which can be selected by digital inputs (dependent on the setting of Parameter
9902 DIGITAL INPUTS FUNCTION SELECT or selected automatically in the case of a mains
power loss if parameter 2006 MAINS LOSS RIDE THROUGH / STOP CONTROL = 2.
When set to 0.0, the drive will coast to stop.
Selects whether the acceleration and deceleration ramps are controlled directly via the
fieldbus, or by internal drive parameters 2202 ACCELERATION RAMP TIME and 2203
DECELERATION RAMP TIME.
Ramps are controlled from internal drive parameters.
Ramps are controlled directly by filedbus.
Sets the proportional gain value for the speed controller when operating in Vector Speed or
Vector Torque motor control modes (parameter 9903 MOTOR CONTROL MODE = 0 ,1,3).
Higher values provide better output frequency regulation and response. Too high a value can
cause instability or even over current trips. For applications requiring best possible
performance, the value should be adjusted to suit the connected load by gradually increasing
the value and monitoring the actual output speed of the load until the required dynamic
behaviour is achieved with little or no overshoot where the output speed exceeds the
setpoint.
In general, higher friction loads can tolerate higher values of proportional gain, and high
inertia, low friction loads may require the gain to be reduced.
Sets the integral time for the speed controller. Smaller values provide a faster response in
reaction to motor load changes, at the risk of introducing instability. For best dynamic
performance, the value should be adjusted to suit the connected load.
Sets the differential gain (%) for the speed controller in vector mode operation (parameter
9903 MOTOR CONTROL MODE = 0).
System Load Inertia to Motor Inertia Ratio entered as H = (JTot / JMot). This value can
normally be left at the default value (10) and is used by the drive control algorithms as a
feed-forward control variable to provide optimum torque current to accelerate the load.
Hence accurate setting of the inertia ratio will produce a better system response and
dynamics. If the value is unknown then leave this set to the default value (10).
Speed bands with which the drive is not allowed to operate.
The Skip Frequency function is used to avoid the ACS255 operating at a certain output
frequency, for example at a frequency which causes mechanical resonance in a particular
machine.
The ACS255 output frequency will ramp through the defined band at the rates set in
parameter 2202 ACCELERATION RAMP TIME and parameter 2203 DECELERATION RAMP
TIME respectively, and will not hold any output frequency within the defined band. If the
frequency reference applied to the drive is within the band, the ACS255 output frequency
will remain at the upper or lower limit of the band.
Defines the center point of the skip frequency band, and is used in conjunction with
Parameter 2500 SKIP FREQUENCY BAND WIDTH.
Def
0.00
0 : Disabled
50.0 %
0.050 s
0.0 %
10
0.0 Hz/Rpm
0.0 Hz/Rpm