Specifications

CHOOSING YOUR SETTINGS
ADVANCED MICRO CONTROLS INC.
3
20
DIP Switch Settings (continued)
Pulse Train Input (SB1-1)
You must define the format of the directional pulses from your indexer. Directional pulses generally have one
of two formats; Step & Direction or CW/CCW. Some indexers can be programmed to output either. Figure
3.4 shows the differences between the two formats and the SD17063’s switch settings for each. The factory
default setting is CW/CCW.
Figure 3.4 Pulse Train Types
The state of the switch is latched on power up. Therefore, you must cycle power to the drive or
activate the Reset Input before the drive recognizes a change to this setting.
Anti-Resonance Disable (SB1-2)
Mid-frequency resonance, which usually occurs between 6 and 20 revolutions per second, is an inherent con-
dition of any conventional stepping motor system. It is due to the influence of the internally generated motor
back-EMF on the motor current. In this unstable range of operation, the motor experiences a velocity modu-
lation which can become sufficiently large to cause a loss of stability and, in extreme cases, even force the
motor to stall.
The drive’s anti-resonance feature, which is Enabled by default, allows the SD17063 to modify the current
waveforms to the motor to dampen the mid-frequency resonance by compensating for the back-EMF. The
feature begins to work at speeds greater than three revolutions per second and has built in hysteresis, which
prevents problems when the motor is running around the three revolutions per second speed.
The anti-resonance feature should be left enabled unless it causes a problem. In very rare instances, a high
degree of mechanical resonance in your system may cause problems for the anti-resonance circuit by causing
mechanical vibrations that are interpreted by the circuit as true motor speed modulations. In these cases, you
will notice an increase in audible noise and a decrease in torque with this feature enabled. Before disabling
the anti-resonance feature, try both settings of the anti-resonance phase feature. (See the next section.) If the
system still runs better without the anti-resonance feature enabled, then disable it.
Anti-Resonance must be disabled before running the SD1763’s Self Test.
Anti-Resonance Phase (SB1-3)
This setting allows you to tune the anti-resonance feature to the inertia of your system. When left at its
default setting of Normal Inertial Load, the SD17063 is tuned for loads with an inertia somewhere between
one and ten times the inertia of the motor’s rotor. If your load’s inertia is less than the inertia of the motor, or
your system has an extremely high torque-to-inertia ratio, then try setting the Anti-Resonance Phase to its
Low Inertial Load setting.
The correct setting will give you the most torque between 6 rps and 20 rps. If you try the Low Inertial Load
setting and do not see an increase in torque or smoother operation, then leave this feature at its Normal Iner-
tial Load setting. As stated above, highly resonant mechanical systems may cause problems for the Anti-Res-
onance circuit. In these rare cases, you will see smoother operation and more torque with the Anti-Resonance
circuit disabled. (See Anti-Resonance Disable section above.)
CW
CW Rotation
CCW
STEP
DIR
CW/CCWSTEP/DIR
CCW Rotation
Directional Inputs