POSIDRIVE
®
FDS 4000
STÖBER
ANTRIEBSTECHNIK
10. Positioning Control
16
Example 1: I30
=
0:ref.input
,
I31
=
0:positive
Since the reference switch divides the total traversing
area into two halves, no other switches are required.
Example 2: I30
=
0:ref.input
,
I31
=
0:positive
The direction defined in
I31
is reversed if the reference
switch is active at the beginning.
Example 3: I30
=
0:ref.input
,
I31
=
0:positive
The reference switch (i.e., cam) only reacts briefly.
A
limit switch
is used for the reversal..
Example 4: I30
=
1:limit input
,
I31
=
0:positive
A limit switch can be used for referencing instead of a
reference switch.
When the power or the external 24 V voltage supply fails, the
information on the reference position is lost. After power
returns,
I37
=1 is used to automatically trigger reference point
traversing with the first start command (i.e.,
posi.start
or
posi.step
).
After a reference point traversing procedure has been
concluded, you can automatically move to any initial position
by programming parameter
I38
(
ref. block
) to the number of
the parameter record to be moved to.
10.7
Position controller
To minimize following error deviation (i.e., difference between
reference value and actual position), the FDS uses speed
precontrol. The maximum permissible following error deviation
specified in
I21
is continuously monitored. The position
controller is running continuously during the entire movement.
v
x
I20
I23
I25
I16
I84
E07
E08
I88
-
-
H23
x x H23* x 60
I08
I07
+
*
H23
(X20 gear ratio factor): Example of position control via X20
The gain of position control
I20
(i.e., the "stiffness" of control)
is called the "Kv factor."
Parameter
I16
(S-ramp) can be used to parameterize reverse-
limited traversing profiles and prevent high-frequency
excitation by a low pass. Time constant
I16
corresponds to a
low-pass limit frequency of fg=2
π
/
I16
.
10.8
Process block chaining
Next block
parameters
J16
,
J26
,
J36
and so on can be used
to chain process blocks into sequences. For example, at the
end of one process block, this can be used to automatically
move to an additional position (i.e., next block). The following
parameters apply to the 1st process block.
•
J16
next block. If
J16
=0, then no chaining.
•
J17
next start. Specifies how next block
J16
is to be started.
•
J18
delay. Applies when
J17
=
1:with delay
For details on
J17
, see the parameter table.
Example 1:
With a rotary attachment, 60° steps are
performed in a continuous cycle with 1-sec
pauses in between.
Solution:
J10
=60°
(Path)
J11
=
0:relative
(Position mode)
J16
=1
(Next block no. 1)
J17
=
1:with delay
(Next start with delay)
J18
=1.000 sec
(delay of 1 sec)
Ö
Process block no. 1 starts itself.
Fast (
I32
)
Zero pulses
Incremental-
encoder
Stop input +
Reference switch
Fast (
I32
)
Zero pulses
Incremental-
encoder
Stop input +
Reference switch
Fast (
I32
)
Slow (
I33
)
Zero pulses
Incremental-
encoder
Reference direction
reversed
Active
Reference switch
fast (
I32
)
Slow (
I33
)
Zero pulses
Incremental
encoder
S ramp
Posi.
speed
n-speed
forward feed
Speed
controller
x-ref.
value
x-actual
deadband Kv factor
Reference value generator
v-ref.
value
n-post
ramp
Following
error
n-motor
Posi-
offset
C31=Kp
C32=Ki
C35=Kp (n=0)
X20-gear
ratio