NI SMD-7613/7614/7615/7616 User Manual
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© National Instruments
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Idle Current/Idle Current Delay
You can reduce motor heating and power consumption by lowering the motor current when it is
not moving. The drive automatically lowers the motor current when it is idle for longer than the
time specified by Idle Current Delay.
The default 50% idle current setting lowers the holding torque to 50% of the specified Running
Current, which is enough to prevent the load from moving in most applications. You can adjust
this value to account for your load and heating requirements.
Load Inertia
The drive 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 specify the innertia
of the load. If you are unsure of this value, you can experimentally find an acceptable value by
entering a multiplier of the rotor inertia.
Control
From the NI Stepper Configuration Utility home screen, click
Motion
icon to open the Motion
Control Mode Window. Select
Pulse & Direction Mode
button to configure the following
settings:
Figure 39.
NI Stepper Configuration Utility Configuration Window
Steps/Rev
You can configure the number of steps per revolution to match the details of your application.
A higher value provides smoother motion, though you may want to configure this value to match
the phsyical parameters of the system such as gearing or screw pitch.
Step Smoothing Filter
At lower step resolutions such as 200 steps per revolution (full step) and 400 steps per revolution
(half step) motors produce more audible noise than when they are microstepped (2,000 steps per
revolution and beyond). The drive includes a feature called microstep emulation, also called step
smoothing, that can provide smooth motion when using full and half steps. If the Steps/Rev setting
is 2,000 or higher, this feature is not needed and can be set to the highest possible value, 2,500.