January 2012 6.16 The Control Loop 899
Module 9158 Maximum torque
With Module 9158 you can limit the torque of an axis or spindle. The maximum
torque resulting from the data in the control's motor table cannot be
exceeded. In this case the torque is limited to the value from the motor
specifications. After the drive is switched off, the original torque becomes
effective again.
If torque limiting is active, the standstill monitoring is inactive; only the motion
monitoring remains active.
The torque-producing current required for the desired torque must be
transferred to the module:
Synchronous motor Asynchronous motor
I
q
: Torque-producing current
M: Desired torque
k
M
: Torque constant
n
N
: Rated speed (from motor
table)
I
N
: Rated current (from motor
table)
P
N
: Rated power output (from
motor table)
Armature control range (n < n
FS
)
Field weakening range (n > n
FS
)
I
q
: Torque-producing current
M: Desired torque
n
N
: Rated speed (from motor table)
n: Current speed
I
N
: Rated current (from motor table)
I
0
: No-load current (from motor table)
P
N
: Rated power output (from motor
table)
n
FS
: Threshold speed for field weakening
(from motor table)
k
M
P
N
I
N
2 π
n
N
60
------
⋅⋅⋅
-------------------------------=
I
q
Mn
N
2 π I
N
2
I
0
2
–⋅⋅⋅⋅
P
N
60⋅
--------------------------------------------------------------=
I
q
Mn
N
n 2 π I
N
2
I
0
2
–⋅ ⋅⋅⋅⋅
P
N
n
FS
60⋅⋅
----------------------------------------------------------------------=
If Module 9158 is used, then certain monitoring functions regarding the
drives must be switched off. Please note the following error messages and
their possible consequences (see DSP error messages)
C380 Motor <axis> not controllable
C3B0 Motor <axis> does not rotate
If you are using a CC 422 controller unit, then please note that the current
values in the oscilloscope are all peak values (and not effective values as
with the CC 424). Measured values then appear greater by a factor of the
square root of 2 than the calculated values.
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