Commissioning
Instruction manual 91/121 V6.3
Derivat. Gain
Minimum Maximum
Units of measure
0
999.00
-
This parameter modifies the derivative time constant of the velocity loop (see drawing 20). Increasing this value tends to anticipate
the motor’s reaction to changes in speed, but the loop can become unstable (you can hear the motor vibrate). Changing this parameter
can be useful in a few cases; generally it is possible to obtain a good functioning of the regulation by modifying appropriately the Pro-
portional and the Integrative parameter.
It is recommended to change this parameter in small steps and test the motor reaction before further changes. When you have found
the right parameter that meets your needs, you can memorise the variations with the “Memo Parameters“ menu (see page 40) and not
before; in this way it will always be possible to return to the previous situation.
Filter PB DComp
Minimum Maximum
Units of measure
0 %
100.00 %
-
This parameter modifies the time constant of the Low Pass filter that is outgoing the D component of the velocity loop (see drawing
20). Increasing this value moves to higher frequencies the size point of the filter; conversely, by decreasing the value, the cut fre -
quency is moved to lower frequencies.
In practical use it can be seen that a high value (i.e. around 100 %) makes the filter transparent, i.e. as if it were not there. Instead, re -
ducing the value makes the motor movement more “soft” and with less noise due to adjustment. When there is a need to increase the
gain of the D component, then it is also advisable to go down with the cut frequency of this filter (i.e. reduce the value) to make the
operation quieter.
Pi Current Loop
Set of parameters to adjust the time constants of the PI adjustment loop on the current.
NOTE:
random change in these parameters can lead to a worsening of the drive’s performance. It is advisable not to change these
values unless strictly necessary and possibly to contact the ALTER technical office for explanations and clarifications. Please note
that it is possible to return the parameters to the value prior to the change simply by removing the voltage from the services and
then returning it or using the ”Restore“ menu (see page 40), always allowed to NOT have already saved the parameters with the
”Memo Parameters“ menu (see page 40).
Proport. Gain
Minimum Maximum
Units of measure
0
99.00
-
This parameter modifies the Proportional time constant of the current loop (see drawing 21). The modification of this parameter is
useful in case of stop of the drive due to the “Overcurrent” alarm; in this case it means that the adjustment is too fast (or too slow) and
the current is not properly controlled by the above alarm. To enter the right parameter it is essential to use the PC connected to the
serial port of the drive and use the software to display the signals of the current loop while the motor is working and decide what to
do.
It is recommended to change this parameter in small steps and test the motor reaction before further changes. When you have found
the right parameter that meets your needs, you can memorise the variations with the ”Memo Parameters“ menu (see page 40) and not
before; in this way it will always be possible to return to the previous situation.
52
Alter Elettronica s.r.l.
Drawing 21 Current loop
IsDem
D/Q
Is Fbk
D/Q
-
P
P gain
I
I gain
Anti
Windup
+
Limit
Vs D/Q
