
BA Intellidrive User’s Manual
Technical Details
Version 1.4
Aerotech, Inc.
7-9
The home limit acts as a reference point so that motion may always begin from the same
physical point in a system. When the controller receives a “Home” command (HO), the
system moves the motor in a preset direction in search of a home limit activation. When
the controller finds the home limit, the motor reverses direction and stops on a preset
occurrence, generally the first occurrence of the encoder’s marker signal after the home
limit has deactivated.
There are two choices to consider when wiring the three limits: active high (normally
closed limit switch) or active low (normally open limit switch). To establish limit
polarity with the controller, follow procedures for setting parameters in
Chapter 4: Parameters.
7.4.3. Hall Effect Interface
AC brushless systems are the only systems that use the Hall effect inputs on P3 of the
controller. The Hall effect switches form a digital representation of the motor phasing that
the microprocessor uses to commutate the motor. This digital representation comprises
three 5 volt signals that form a digital six step pattern. The controller receives these
signals with a circuit that is electrically identical to the limit input circuit. Refer to
Figure 7-8 for Hall effect input circuitry.
Figure 7-8.
Hall Effect Input Circuit
Aerotech brushless rotary motors are shipped from the factory with the correct motor
phase to Hall effect device relationship established. This is essential for proper motor
commutation. The parameter that affects this relationship is PRM:27 and is set at “0”.
Figure 7-9 and Figure 7-10 illustrate the proper Hall effect and motor phasing for both
CW and CCW motor rotation (viewed looking into the mounting flange of the motor).
During CW motor rotation each Hall effect signal is at a logic low state when its
corresponding motor phase is at a positive voltage. During CCW rotation each Hall effect
signal is at a logic high state when its corresponding motor phase is at a positive voltage.
HALL A
HALL B
HALL C
P3
10
5
11
10K (x3)
10K
10K
10K
.01uF
.01uF
.01uF
S1
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