Specifications

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INSTALLING THE SD17063
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Step 6: Testing the System (continued)
Determining Current Loop Gain (continued)
4) Apply power to the SD17063. You should hear at least one sound from the motor in the 3 to 5 KHz
range that subjectively sounds like AM radio hiss. This is normal. You may also hear a much higher
pitched sound in the 10 KHz range. If you do, set the Current Loop Gain setting to REDUCED 1.
(SB1-4 = 0 and SB1-5 = 1.) This should eliminate the higher pitched sound. If you still hear it, try the
REDUCED 2 and 3 settings. The first setting that eliminates the higher pitched sound is the setting
you should use. If you do not hear any changes to the sounds from the motor when testing the
different settings, then use the TYPICAL setting.
5) After documenting your Current Loop Gain setting, restore all other settings to the values you
documented at the beginning of this procedure.
A low inductance stepper motor can have an excessive amount of overshoot and ringing at the start or end of
a move. Adjusting the Current Loop Gain dampens the amount of overshoot and ringing. That is why we
instruct you to use the lowest REDUCED setting that eliminates the high pitched sound. Using a higher set-
ting will overdampen the system. The system will still work when using a higher setting, and nothing will be
harmed, but the motor will take sightly longer to reach its target position.
Determining Anti-Resonance Setting
Anti-Resonance is set by trial and error. The setting that gives you the best performance is the setting to use.
Because the load on the motor affects the resonance points, the final settings cannot be determined until the
machine is operational.
The Anti-Resonance feature affects motor performance when the motor’s speed is between 3 and 20 rps. All
stepper motors experience resonance problems where they run “rough” at certain speeds. At these speeds, the
motor cannot run at the commanded velocity and its true velocity oscillates around the commanded value.
The Anti-Resonance feature monitors the current feedback from the motor to detect when resonance occurs
and modifies the current waveforms to compensate. A vast majority of systems will work best with the Anti-
Resonance feature Enabled, (SB1-2=0, which it is by default), and the Anti-Resonance Phase feature set to
Normal Inertial Load, (SB1-3=0, also the default). These settings should be used unless your machine is
experiencing resonance problems. Resonance problems are typically rough operation and increased audible
noise at specific speeds.
If you are experiencing resonance problems with the Anti-Resonance and Anti-Resonance Phase settings at
their defaults, try setting the Anti-Resonance Phase to its Low Inertia Setting, (SB1-3=1). This setting has its
greatest effect when the inertia of your load is less than the inertia of your motor, or you have a very high
torque-to-inertia ratio. Values for the inertia of AMCI Motors can be found in Table 2.5, Stepper Motor
Specifications found on page 16.
Finally, the resonance of some mechanical loads can interfere with the Anti-Resonance feature. When this
occurs, the Anti-Resonance feature tries to compensate at the wrong speeds and actually makes operation
worse. In these rare instances, you should disable the Anti-Resonance feature, (SB1-2=1). If your system
runs better with the Anti-Resonance feature totally disabled, then this is the setting you should use.
Determining Output Waveform Setting
When full stepping the motor, (200 Step/Rev), you must leave the Output Waveform setting to
Pure Sine. Using any other setting will put the SD17063 in Self-Test mode.
Like Anti-Resonance, the Output Waveform setting is determined by trial and error. The setting that gives
you the best performance is the setting to use. However, if you do not see any performance gains when using
the reduced waveforms, use the Pure Sine setting because the motor runs most efficiently with this setting.
When trying the different Output Waveform settings watch for smoother operation. If you are using the step-
per motor to finely position a load, also look for an improvement in positional accuracy. the setting that yields
the smoothest operation and/or best positional accuracy is the setting to use. You will not harm the motor or
drive if you reduce the current waveform too much while testing the system.