HCTL1100 Datasheet, PDF (35/40 Pages) Agilent(Hewlett-Packard) – General Purpose Motion Control ICs

35
Figure 14. Trapezoidal Profile Mode.
two’s-complement final position is
written to registers R2BH, (MSB),
R2AH, and R29H (LSB). The 16-
bit command acceleration resides
in registers R27H (MSB) and
R26H (LSB). The command
acceleration has the same integer
and fraction format as discussed
in the Integral Velocity Control
mode section. The 7-bit maximum
velocity is a scalar value with the
range of 00H to 7FH (0D to
127D). The maximum velocity
has the units of quadrature counts
per sample time, and resides in
register R28H. The command
data registers may be read or
written to in any order.
The internal profile generator
produces a position profile using
the present Command Position
(R0CH-R0EH) as the starting
point and the Final Position
(R2BH-R29H) as the end point.
Once the desired data is entered,
the user sets flag F0 in the Flag
register (R00H) to commence
motion (if the HCTL-1100 is
already in Position Control
mode).
When the profile generator sends
the last position command to the
Command Position registers to
complete the trapezoidal move,
the controller clears flag F0. The
HCTL-1100 then automatically
goes to Position Control mode
with the final position of the
trapezoidal move as the command
position.
When the HCTL-1100 clears flag
F0 it does NOT indicate that the
motor and encoder are at the final
position NOR that the motor and
encoder have stopped. The flag
indicates that the command
profile has finished. The motor
and encoder’s true position can
only be determined by reading the
Actual Position registers. The only
way to determine if the motor and
encoder have stopped is to read
the Actual Position registers at
successive intervals.
The status of the Profile flag can
be monitored both in the Status
register (R07) and at the external
Profile pin at any time. While the
Profile flag is high NO new
command data should be sent to
the controller.
Each sample time, the internal
profile generator uses the
information which the user has
programmed into the Maximum
Velocity register (R28H), the
Command Acceleration registers
(R27H and R26H), and the Final
Position registers (R2BH, R2AH,
and R29H) to determine the value
which will be automatically loaded
into the Command Position
registers (R0EH, R0DH, and
R0CH). After the new command
position has been generated, the
difference between the value in
the Actual Position registers
(R12H, R13H, and R14H) and the
new value in the Command
Position registers is calculated as
the new position error. This new
position error is used by the full
digital compensation filter to
compute a new motor command
output for the sample time. (The
register block diagram in Figure 3
further shows how the internal
profile generator works in
Trapezoidal Profile mode.)