National Instruments NI ISM-7401, Руководство пользователя, Страница: 13 / 31

NI ISM-7401/7402 User Manual
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© National Instruments
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Switches 1 and 2 on the front of the NI ISM-7401/7402 control the percent of rated current that
is applied to the motor. Set them according to the illustration below.
Figure 17.
Configuring Current on Switches 1 and 2
Setting Idle Current
You can also reduce motor heating and power consumption by lowering the motor current when
it is not moving. The NI ISM-7401/7402 automatically lowers the motor current when it is idle
to either 50% or 90% of the running current. The 50% idle current setting lowers the holding
torque to 50%, which is enough to prevent the load from moving in most applications. This
reduces motor heating by 75%. Some applications, such as those supporting a vertical load,
require a high holding torque. In such cases, set the idle current to 90% as shown in the following
figure.
Figure 18. Configuring Idle Current on Switch 3
Load Inertia
The NI ISM-7401/7402 includes anti-resonance and electronic damping features which greatly
improve motor performance. To perform optimally, the drive must understand the
electromechanical characteristics of the motor and load. Most of this is completed automatically
in the factory during motor and drive assembly. To further enhance performance, you must set
a switch to indicate the approximate inertia ratio of the load and motor. The ranges are 0 to 4X
and 5 to 10X. Divide your load inertia by the NI ISM-7401/7402 rotor inertia (82 g-cm2) to
determine the ratio, then set switch 7 accordingly, as shown below.
Figure 19.
Configuring Load Inertia on Switch 7