Selection
number
Selection name
Description
B0
Stator resistance identification Identify the stator resistance during the start magnetisation.
B3
Limit frequency polarity
B6
Enable IR-compensation adjust
B8
Voltage based current limit
B14
Ramp anti-windup
Use the ramp anti-windup control.
The bit B0 enables stator resistance identification at each start. It cannot be used when a
start is made to a rotating motor. It is recommended when a start is always made from
standstill.
The temperature has an effect on the stator resistance value. A correct resistance value is
necessary for the advanced sensorless control, especially at low frequencies. The
temperature effect is mitigated, when instead of using a value that was identified in the first
identification run, the resistance is identified at each start.
When you set the bit to 1, the stator resistance is identified during the start magnetisation.
For this to happen, enable the start magnetisation function with P3.4.3.1 Start Magnetising
Current and P3.4.3.2 Start Magnetising Time. For induction motors, start magnetising is
enabled already when the identification run is made.
Bit B3 can be used to improve the robustness in applications that require high torque at low
speeds but that do not require speed reversals with full load and also do not operate with
substantial load on the generator side at low frequencies. An example of a suitable
application is an extruder.
When you select bit B3, the sign (+ or -) of the output frequency is limited according to the
sign of the user frequency reference. When positive frequency reference is used, the output
frequency is limited to positive values. When negative frequency reference is used, only
negative output frequency is allowed. As a result, the operation is limited in an area where
any parameter fault has the most significant effect. This improves the robustness of the
control.
Bit B6 is targeted to enable robustness improvement in applications that do not require high
torque at low frequencies.
When bit B6 is activated, you can adjust the IR compensation in the same way as in a normal
open loop control using parameter P3.1.4.10 Torque Boost Motor Gain. When the gain value
is reduced, sensitivity against parameter faults is also reduced and robustness is improved.
Reducing the gain value also reduces torque capability at low frequencies.
Bit B8 activates a function that reduces the risk of the control system getting stuck in the
current limit at low frequencies by limiting the motor voltage. This could occur because of
errors in the parameter settings. The function is active only when the output frequency is
less than 1.0 Hz.
Use the bit B8 only if the nature of the process allows it, because otherwise it can lead to loss
of performance due to limited voltage. Bit B8 can be used if there is no need to run against
VACON · 212
PARAMETER DESCRIPTIONS
10
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