II K 4-32
Overview of Software
4.5.5 Armature current controller
The Arm Cur Nom (1.01), Arm Cur Max (3.04),
Torque Lim Pos (3.07) and Torque Lim Neg (3.08)
parameters are the ones relevant to the current limi-
tation functions. Arm Cur Nom (1.01) scales the
power converter to motor rated current. All other
current-dependent parameters are referenced to this
parameter. Arm Cur Max (3.04) limits the current
controller absolutely. Torque Lim Pos (3.07) and
Torque Lim Neg (3.08) limit the reference value
span.
For the self-optimisation function, only the Arm Cur
Nom (1.01) is relevant. The current controller is
always optimised to 100 %, since the system will more
usually be running in the machine's operating point
than in overload. If you want to optimise to overload,
then the Arm Cur Nom (1.01) must be temporarily set
to overload, then optimized, and subsequently reset
again.
Example of an overload parameterization routine
by means of fixed parameter settings:
e.g.
Motor nominal current = 170 A
Overload = 150%
Speed reference = analogue input AI1
Parameters affected
Arm Cur Nom (1.01) = 170 A
Arm Cur Max (3.04) = 150%
Overload Time (3.05) = 60 s (*)
Recovery Time (3.06) = 900 s (*)
Torque Lim Pos (3.07) = 150%
Torque Lim Neg (3.08) = -150%
Cur Contr Mode (3.14) = Speed Contr resp. Mac-
ro depend
é
Overload
fix
Speed Ref Sel (5.01) = AI1 resp. Macro depend
(*) The particulars given here for Overload Time and
Recovery Time are to be construed as examples only.
The actual figures will depend on the overload with-
stand capabilities of the drive components (motor and
power converter), and must be covered by the plan-
ning work.
Second current limitation
The motor’s maximum armature current is limited by
the Arm Cur Max (3.04) parameter. This absolute
limitation is always active. Under this, a second
current limitation function, Arm Cur Lim 2 (3.24),
switched on and off by a binary signal, can be activat-
ed in the Curr Lim 2 Inv (9.17) parameter. This
means it is possible to switch back and forth digitally
between these two limitation functions. The digital
inputs DI1 to DI4 are available as binary signals. With
serial communication, this limitation function can also
be switched over using Bits 11 to 15 of the Main
Control Word.
If the second current limitation function has been
activated in parameter group 9 - Macro Adaptation,
the value of the Arm Cur Max (3.04) parameter must
be greater than the value of Arm Cur Lim 2 (3.24). In
addition, the Torque Lim Pos (3.07) and Torque Lim
Neg (3.08) parameters must to set in accordance with
Arm Cur Max (3.04).
The Arm Cur Max (3.04) parameter limits the current
to the maximum permissible armature current. This
limitation function is always active, even when the
second current limitation function has not been pa-
rameterised, Curr Lim 2 Inv (9.17) = Macro depend
or Disable or Arm Cur Lim 2 (3.24) is greater than the
value of Arm Cur Max (3.04).
120%
150%
150%
-150%
Arm Cur Max
(3.04)
Arm Cur Lim 2
(3.24)
Curr Lim 2 Inv (9.17)
Armature Current Limitation
Parameter group 9
Second Current
Limitation
Torque Lim Pos
(3.07)
Torque Lim Neg
(3.08)
Torque Limitation
Bin. signal:
DI1 … DI4
MCW Bit 11 … 15
0 =
$UP&XU/LP
active
1 =
$UP
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