Hitachi X200 Series instruction manual 16, Velocity Profiles

Velocity Profile

1−16

Getting started

Velocity Profiles

The X200 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.

Speed Set speed

Accel Decel

0

t

Acceleration and deceleration settings specify	Speed	Maximum speed
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,	0
while a decrease uses the deceleration slope.				t
			Acceleration
The accel or decel time a particular speed			(time setting)
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	Speed
speeds. And, it can apply separate acceleration		Speed 2
and deceleration transitions from any preset to
		Speed 1
any other preset speed. A multi-speed profile
(shown at right) uses two or more preset speeds,	0
which you can select via intelligent input
		Multi-speed Profile	t
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.

Speed	Forward move
0	t
	Reverse move

Bi-directional Profile

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.