Hitachi WJ200-001L, Инструкция по эксплуатации, Страница: 45 / 680

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Velocity Profiles
The WJ200 inverter is capable of sophisticated
speed control. A graphical representation of that
capability will help you understand and
configure the associated parameters. This
manual makes use of the velocity profile graph
used in industry (shown at right). In the
example,
acceleration is a ramp to a set speed,
and
deceleration
is a decline to a stop.
Acceleration and deceleration settings specify
the time required to go from a stop to maximum
frequency (or vise versa). The resulting slope
(speed change divided by time) is the
acceleration or deceleration. An increase in
output frequency uses the acceleration slope,
while a decrease uses the deceleration slope.
The accel or decel time a particular speed
change depends on the starting and ending
frequencies.
However, the slope is constant, corresponding to the full-scale accel or decel time
setting. For example, the full-scale acceleration setting (time) may be 10 seconds – the
time required to go from 0 to 60Hz.
The WJ200 inverter can store up to 16 preset
speeds. And, it can apply separate acceleration
and deceleration transitions from any preset to
any other preset speed. A multi-speed profile
(shown at right) uses two or more preset speeds,
which you can select via intelligent input
terminals. This external control can apply any
preset speed at any time.
Alternatively, the selected speed is infinitely variable across the speed range. You can
use the potentiometer control on the keypad for manual control. The drive accepts
analog 0-10VDC signals and 4-20 mA control signals as well.
The inverter can drive the motor in either
direction. Separate FW and RV commands
select the direction of rotation. The motion
profile example shows a forward motion
followed by a reverse motion of shorter duration.
The speed presets and analog signals control
the magnitude of the speed, while the FWD and
REV commands determine the direction before
the motion starts.
NOTE
NOTE NOTE NOTE: The WJ200 can move loads in both directions. However, it is not designed for
use in servo-type applications that use a bipolar velocity signal that determines
direction.
Speed
0
Velocity Profile
t
Accel Decel
Set speed
Speed
0
t
Maximum speed
Acceleration
(time setting)
Speed
0
Multi-speed Profile
t
Speed 1
Speed 2
Speed
0
Bi-directional Profile
t
Forward move
Reverse move