Hitachi CONVENTION 14 Instruction Manual page 44

Velocity Profiles
The X200 inverter is capable of sophisticated
speed control. A graphical representation of that
capability will
configure the associated parameters. This
manual makes use of the velocity profile graph
used in industry (shown at right). In the
acceleration
example,
deceleration
and
Acceleration and deceleration settings specify
the time required to go from a stop to maximum
frequency (or vise versa). The resulting slope
(speed change
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 X200 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
magnitude of the speed, while the FWD and
REV commands determine the direction before
the motion starts.
NOTE: The X200 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.
help you understand
is a ramp to a set speed,
is a decline to a stop.
divided by time)
analog signals control
Speed
and
Accel
0
Velocity Profile
Maximum speed
Speed
is the
0
Speed
Speed 1
0
Multi-speed Profile
Speed
Forward move
0
the
Bi-directional Profile
1 − 23
1 23
Set speed
Decel
t
t
Acceleration
(time setting)
Speed 2
t
t
Reverse move