Hitachi Vector Control with the SJ300 Inverter Application Note page 14

[3] Positioning under ASR mode (Orientation function) (V2 mode)
This can be implemented using
(3-1) Orientation Function
The SJ300 series incorporates a function where the inverter counts the pulses from the motor encoder
and stops after a certain number of pulses. It is called the orientation function.
The Orientation function is used when an accurate stop position is required.
The SJ300 does not count encoder pulses every time, which means it is different from servo drives. The SJ300
starts counting the encoder pulses only after the Z pulse is given during orientation mode. Therefore the
SJ300 can stop the motor at a certain position.
First, it is necessary to go into the orientation mode. (Turn the "ORT " terminal ON on the logic
s
card.) During orientation period, INV stops the motor after certain pulses from Z pulse is given.
<Example of stopping 7pulses after Z pulse is given>
Orientation mode
ORT input
Z pulse
(1 pulse / rotation)
A pulse
fout
0
Fig 3. Example of positioning
Parameter set for this example under following condition is in table below.
1024 ppr encoder
-
2.0 Hz of orientation speed
-
acceptable positioning range is 7 3 pulses
-
- give frequency command from the analog input (O-L)
give RUN command from the digital panel
-
No. Code
1 A044 Control method
2 P011 ppr of the encoder
3 P012 Control mode
4 P013 Mode of the pulse train input
5 P014 Stop position while orientation
6 P015 Speed while orientation
7 P016 Direction of orientation
8 P017 Orientation completion range
9 A001 Frequency command from;
10 A002 RUN command from;
11 F002 Acceleration time
F003 Deceleration time
© 2002 Hitachi America, Ltd.
SJ-FB ( feed back option card
Positioning mode
• ‚ ƒ „
Orientation speed [P015]
Contents Set value
14
).
... † ‡
Stop!
The ramp is based on the position loop
gain [P023], and does not follow the set
ramp time [F003].
Big [P023] results in a quick stop.
05 V2 (closed loop control)
1024 Depends on the encoder
00 ASR (Speed command base on speed)
- No need to care because this is ASR mode
28 [P014] = 4096 * 7 / 1024 = 28
2.0 In case of 2.0Hz for orientation speed.
00 In case of FW rotation
12 Allowable deviation of positioning.
[P017] = 3 * 4
(Multiplying 4 is fixed as MCU calculation)
01 Terminal (O-L input)
02 "RUN" key of the operator
3.0
As short as the system allows.
3.0
s
Orientation mode starts
when the actual output
frequency reaches
the orientation speed.
s
Deceleration to the
orientation speed is based on
the set deceleration time.
Remarks