Hitachi SJ Series User Manual page 214

Chapter 12
12.8.5 Change the acceleration or
deceleration pattern
Q
• To reduce such a large shock caused by an abrupt
movement that will collapse the load being
transported in lifts or on conveyors.
• To reduce the shock when the motor starts moving
and when it is about to stop moving.
• To change the acceleration gradient in accordance
with the winding or feeding amount.
A
• Setting a(n) acceleration or deceleration pattern is
possible that suit each system.
• Setting the acceleration pattern selection and the
deceleration pattern selection can be done
independently of each other by means of [AC-03]
and [AC-04], respectively.
• To use a(n) acceleration or deceleration pattern
other than the linear one (00), a stable operation
can be achieved by an command that can fix the
target of the frequency command by means of the
operator-keypad command and/or the multi-speed
command.
• Even if a(n) acceleration or deceleration pattern is
set, the acceleration time should be set at the time
that it takes to rise from 0 Hz to the maximum
frequency and the deceleration time should be set
at the time it takes to fall from the maximum
frequency to 0 Hz.
Pattern selection
Select a pattern for each of the acceleration and the deceleration patterns by referring to the following table.
Set 00
value
Curve Linear
[AC-03]
(Accele
ration)
Time
[AC-04]
(Decele
ration)
Time
Providing a linear
acceleration up or
Descrip
deceleration down to
tion
the set frequency
value.
01
S-shaped
Time
Time
Effective in the Effective when a winder or the like needs to
prevention of load control of the tension and/or prevent the
collapse in lifts or on object to be wound from being cut. Usable
for 1-shot winding/feeding.
conveyors, for
example.
12-8-9
!
• Changing the acceleration or deceleration pattern
from one to another will create a sector with a(n)
acceleration or deceleration time having a steep
gradient. If the occurrence of an over current/over
voltage is predictable, it will be prevented by
adjusting from happening, the acceleration or
deceleration time has to be adjusted to prevent
such an occurrence.
• When any other acceleration or deceleration
pattern than the linear one (00) is set, a change of
command value during the acceleration or
deceleration may cause a recalculation of the
acceleration or deceleration pattern, which may
result in a shock.
• When any other acceleration or deceleration pattern
than the linear one (00) is set, use any other
command than the analog input one. An unsteady
command value may cause a recalculation of the
acceleration or deceleration pattern, which may
prolong the actual acceleration or deceleration
time.
02 03
U-shaped Inverse-U- shaped
Time
Time
Inverter Function
04
EL-S-shaped
Time
Time
Time
Time
Providing a shockless
start/stop as in the case
of the S-shaped curve,
but providing a linear
middle sector.