Hitachi WJ C1 Series User Manual

Chapter 9 Inverter Functions
9-14-4
2 Positioning Operation
 The positioning operation when the RUN command is turned on is shown in the figure below.
(1) When an RUN command is specified (1-1), the positioning operation starts automatically
(1-2), following the trapezoidal operation pattern shown above, according to the position
set-point, speed command (frequency command), acceleration time, and deceleration time
selected from each respective command source at that time. The rotation direction is
forward rotation if (target position - current position) is positive, and reverse rotation if
(target position - current position) is negative.
(2) The operation accelerates according to the acceleration time until it reaches the speed
command (frequency command). If the amount of movement to the target position is small,
it decelerates before reaching the speed command (dashed line in the figure).
If the amount of movement is smaller than "Position displacement at creep speed [P014]",
it moves to the target position at the "Creep speed [P015]", and if the amount of movement
is within "Positioning completed range [P017]", the DC braking is activated on the spot.
(3) Deceleration starts before the target position (before "the amount of movement during
deceleration" + "Position displacement at creep speed [P014]").
(4) The operation decelerates and when the output frequency reaches "Creep speed [P015]",
operates at that speed.
If the motor rotation becomes unstable at the low speed, increase [P015].
(5) When the current position reaches within [the target position ± "Positioning completed
range [P017]"], the "Positioning completed [POK]" output is turned on, and it decelerates
and stops.
(6) The DC braking activates after stopping. When the RUN command is turned off, the DC
braking is released.
Since the DC braking after stopping is not controlled to maintain the position, the stop
position may shift if an external force is applied. Use an external brake if the position needs
to be maintained.
 For the single-phase pulse input ([P004]=00), the position is not counted if the motor is rotated
at the stopped state without RUN command input. To prevent the position from shifting during
stop, use a brake or other means to prevent the motor shaft from rotating during stop, or change
to the phase AB 90° phase difference pulse so that position counting is performed even during
stop.
 For the single-phase pulse input ([P004]=00), if the rotation direction command is switched
during operation, an error may occur in the position count due to the time difference between
the switching of the inverter's output frequency direction and the switching of the actual motor
rotation direction. Controlling the position at the single-phase pulse input, be sure to
completely stop the operation, and then change the rotation direction.
ON
Output
frequency (Hz)
Speed
command
RUN command
ON
Creep speed [P015]
[POK] output
If smaller position set-
point is specified, it
decelerates without
reaching the speed
command, and the
positioning is completed.
DC braking (DB)
Position displacement at creep speed [P014]
Time
The area of this trapezoidal
operation pattern is the amount
of movement (target position).
(1-1)
(1-2)
(2)
(3)
(4)
(5)
(6)
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Hitachi WJ C1 Series Specifications

General

Brand	Hitachi
Model	WJ C1 Series
Category	Inverter
Language	English