Velocity Profiles; Multi-Speed Profile; Bi-Directional Profile - Omron 3G3MX2 User Manual

Introduction to Variable-Frequency Drives
1-3-8

Velocity Profiles

The MX2 inverter is capable of
sophisticated speed
graphical representation
capability will help you understand
and configure the associated param-
eters. This manual makes use of the
velocity profile graph used in indus-
try (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 set-
tings 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 par-
ticular 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 60 Hz.
The MX2 inverter can store up to 16
preset speeds. And, it can apply
separate acceleration and decelera-
tion 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 0-10 VDC 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 sig-
nals control the magnitude of the
speed, while the FWD and REV
commands determine the direction
before the motion starts.
Note The MX2 can move loads in both directions. However, it is not designed for
use in servo-type applications that use a bipolar velocity signal that deter-
mines direction.
Speed
control. A
of that
0
Speed
0
Speed
Speed 1
0
Speed
Forward move
0
Section 1-3
Set speed
Accel Decel
Velocity Profile
Maximum speed
Acceleration
(time setting)
Speed 2
Multi-speed Profile
Reverse move
Bi-directional Profile
t
t
t
t
17