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Quattro DC Drive S-Curves A2
S-Curves A2 submenu
The drive speed command is passed through
an internal S-curve in order to produce the
speed reference. In general, the S curve
function takes an arbitrary speed command
and generates a speed reference subject to
the conditions that the maximum accel, decel
and jerk rates not be exceeded. The speed
command is typically the target speed that the
reference is headed to.
If the user gives the drive a speed dictation,
either analog or serial, the S-Curve will act as
a slew rate limiter on the externally generated
speed dictation. For this purpose, set the jerk
rates associated with the S-Curve (see Table 3
for determining which s-curve is used) to zero
and the Accel Rate and Decel Rate to values
faster than the maximum expected rated
provided in the dictation signal.
Below shows the six parameters associated
with an S-Curve data set:
• Accel - Maximum allowed acceleration rate
(ft/s
2
or m/s
2
)
• Decel - Maximum allowed deceleration rate
(ft/s
2
or m/s
2
)
• Accel Jerk In - Maximum allowed change in
acceleration towards Accel (ft/s
3
or m/s
3
)
• Accel Jerk Out - Maximum allowed change
in acceleration from Accel (ft/s
3
or m/s
3
)
• Decel Jerk In - Maximum allowed change in
deceleration towards Decel (ft/s
3
or m/s
3
)
• Decel Jerk Out - Maximum allowed change
in deceleration from Decel (ft/s
3
or m/s
3
)
The S-curves are specified by four parameters:
acceleration rate (ft/s
2
or m/s
2
), deceleration
rate (ft/s
2
or m/s
2
), leveling jerk rate (ft/s
3
or
m/s
3
), and jerk rate (ft/s
3
or m/s
3
).
Since an adjustable jerk rate is helpful for
smooth landings, the jerk rates are split for
ease in elevator fine-tuning. The jerk rate
parameters specify: acceleration from the floor
(ACCEL JERK IN), jerk out of acceleration
(ACCEL JERK OUT), jerk into deceleration
(DECEL JERK IN), and the leveling into the
floor (DECEL JERK OUT).
S-Curve
There are four S-curve patterns available in
the drive and each S-curve is customized by
six parameters:
Parameters for S-curve-0 (SC0):
• ACCEL RATE 0, DECEL RATE 0, ACCEL
JERK IN 0, ACCEL JERK OUT 0, DECEL
JERK IN 0, and DECEL JERK OUT 0
Parameters for S-curve-1 (SC1):
• ACCEL RATE 1, DECEL RATE 1, ACCEL
JERK IN 1, ACCEL JERK OUT 1, DECEL
JERK IN 1, and DECEL JERK OUT 1
Parameters for S-curve-2 (SC2):
• ACCEL RATE 2, DECEL RATE 2, ACCEL
JERK IN 2, ACCEL JERK OUT 2, DECEL
JERK IN 2, DECEL JERK OUT 2
Parameters for S-curve-3 (SC3):
• ACCEL RATE 3, DECEL RATE 3, ACCEL
JERK IN 3, ACCEL JERK OUT 3, DECEL
JERK IN 3, DECEL JERK OUT 3
S-Curve Pattern Selection
The default S-curve pattern is S-curve-0
(SC0). To make the other patterns available,
the user must assign S-CURVE SEL 0 and/or
S-CURVE SEL 1 as logic input(s). The logic
input(s) can then be used to select one of the
S-curve patterns, as follows:
Logic Inputs
Assigned
S-curves
Available
None SC0 only
SEL 0 only SC0 or SC1
SEL 1 only SC0 or SC2
SEL 0 & SEL 1 SC0, SC1,
SC2 or SC3
Table 3: S-Curve Availability
logic input
S-CURVE
SEL 1 SEL 0
S-curve
selected
0 0 SCO
0 1 SC1
1 0 SC2
1 1 SC3
Table 4: Selecting S-Curves
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