HCTL1100 Datasheet, PDF (25/40 Pages) Agilent(Hewlett-Packard) – General Purpose Motion Control ICs

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to do its calculations is given by
the Minimum Limits of R0FH
(Sample Timer Register) as shown
in Table 4. For Position Control
Mode, the user should wait for the
Sample Timer to count down 07H
from its programmed value before
writing the next command
position or velocity. If the
programmed sample timer value
is 39H, wait until the Sample
Timer Register reads 32H.
Writing between 32H and 00H
will make the command informa-
tion available for the next sample
period.
Commutator
Status Register
Commutator Ring
X Register
Y Phase Overlap
Offset
Max. Phase Advance
Velocity Timer
(R07H)
(R18H)
(R1AH)
(R1BH)
(R1CH)
(R1FH)
(R19H)
Phase advance allows the user to
compensate for the frequency
characteristics of the motor/
amplifier combination. By
advancing the phase enable
command (in position), the delay
in reaction of the motor/amplifier
combination can be offset and
higher performance can be
achieved.
Phase offset is used to adjust the
alignment of the commutator
output with the motor torque
curves. By correctly aligning the
HCTL-1100’s commutator output
with the motor’s torque curves,
maximum motor output torque
can be achieved.
The inputs to the Commutator are
the three encoder signals,
Channel A, Channel B, and Index,
and the configuration data stored
in registers.
The Commutator uses both
channels and the index pulse of
an incremental encoder. The
index pulse of the encoder must
be physically aligned to a known
torque curve location because it is
used as the reference point of the
rotor position with respect to the
Commutator phase enables.
The index pulse should be
permanently aligned during motor
encoder assembly to the last
motor phase. This is done by
energizing the last phase of the
motor during assembly and
permanently attaching the
encoder codewheel to the motor
shaft such that the index pulse is
active as shown in Figures 7
and 8. Fine tuning of alignment
for commutation purposes is done
electronically by the Offset
register (R1CH) once the com-
plete control system is set up.
The commutator is a digital state
machine that is configured by the
user to properly select the phase
sequence for electronic
commutation of multiphase
motors. The Commutator is
designed to work with 2, 3, and 4-
phase motors of various winding
configurations and with various
encoder counts. Along with
providing the correct phase
enable sequence, the Commutator
provides programmable phase
overlap, phase advance, and
phase offset.
Phase overlap is used for better
torque ripple control. It can also
be used to generate unique state
sequences which can be further
decoded externally to drive more
complex amplifiers and motors.
Figure 7. Index Pulse Alignment to Motor Torque Curves.