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Synchronizing controller
MG.10.N4.02 - VLT is a registered Danfoss trademark
43
Setting the parameters
For this work we recommend you to have the description of parameters at hand. See the VLT
5000/VLT5000Flux Operating Instructions.
NOTE: It is very important that the VLT is optimized for the motor before optimizing the
Synchronizing controller. First you record the motor data and perform an AMA (Automatic Motor
Adaptation) if possible and then you can start programming your synchronization functions.
Parameter 205 Maximum reference: Set the frequency for a value that is about 10% higher
than the maximum value of parameter 716.
Example:
Motor 7.5 kW, 1460
1
/
min
at 50 Hz, speed of the application approx. 1800
1
/
min
1
,
1
*
*
Nom
n
Applicatio
Nom
N
N
f
=
50
1800
1460
11
1
1
Hz *
* ,
min
min
= 62Hz maximum ref. value
Parameter 221 Torque limit for motor mode: Set for maximum. – Choose a lower value, if
special safety precautions are necessary.
Parameter 222 Torque limit for regenerative operation: Set for maximum. – Choose a lower
value, if special safety precautions are necessary
Parameter 701
Record “1” to start the test program.
Parameter 709 This parameter configures the velocity filter for speed synchronization. Since
speed synchronization is based on speed a small fluctuation in master speed,
when running at low speed, can have an effect on the pid loop control. Hence
this filter will even out the effect.
Cmdvel = Old_ (Actvel – Old_Cmdvel) * ms/tau_filt
Cmdvel
= set velocity
Old_Cmdvel
= last set velocity
Actvel
= actual velocity of master
ms
= sample time (parameter 777)
tau_filt
= filter time constant
For standard encoders the following table can be used:
Encoder resolution
Tau_filt (ms)
250 39500
256 38600
500 19500
512 19000
1000 9500
1024 9300
2000 4500
2048 4400
2500 3500
4096 1900
5000 1400