ETEL Doc. - Operation & Software Manual # DSC2P 903 / Ver. F / 3/6/05
Chapter C: System functions
Operation & Software Manual
Direct Drives & Systems
167
conversion formulae of these units into the IS0 system are given in
Parameter K50 appearing at the
denominator of the formula decreases the position, speed and acceleration
user resolution
in case of the
values exceed the maximum controlled by the controller without going over the system’s performances.
Example (for the DSC2P/DSC2V):
Supposing that a movement with a speed of 1 m/s is planned with a linear motor with a 4
µ
m period encoder.
Parameters K77 and K50 are chosen with respective values of 8 and 0, and a sampling period of h=166.67
µ
s.
The conversion equation of the user speed increment unit [usi] gives the speed to be programmed in user
increment:
Remark:
The same calculation can be done for the DSCDP, DSCDL and DSCDM but h = 500
µ
s.
A speed of 2,8 billion increment exceeds the maximum value the controller can control, which is of 2 billion. It
is therefore impossible to reach the 1m/s requested in this configuration even though the motor and the
encoder system easily allow it. To change this, the value 1 is introduced in parameter K50 of the above formula.
A speed of 1,4×10
9
[usi] for 1 m/s is then obtained and this value is accepted by the controller.
Remark:
Increasing parameter K50 diminishes the system’s position, speed and acceleration resolution.
However the controller’s internal calculations (the regulator e.g.) do not include this parameter
and the resolution is not decreased.
Parameter
K77
) determines the smallest distance an
analog encoder
(resolution) can
measure (this is parameter
K69
for
TTL encoders
). Increasing parameter K77 (or K69) allows also to diminish
gain values in the position regulator if they are too big. In the end only the user distance is divided by 2
K50
in
order to avoid to be too high and to exceed the maximum limit. The same operations can be made with the
other cinematic quantities such as speed, acceleration and jerk.
13.3.11 Movements equations
Note:
The understanding of these equations is not necessary to operate the controller, they are given
only for information.
13.3.11.1 Constantly accelerated linear movement (CALM)
A
CALM
is a movement with a constant acceleration. The movement trajectory of a constantly accelerated
linear movement is described by the following equation:
Available on
DSC2P
DSC2V
DSCDP
DSCDL
DSCDM
Speed [usi]
Speed [m/s]
256 1024 2
K
77
h
⋅
⋅
⋅
PCod 2
K
50
⋅
------------------------------------------------ 1 256 1024 2
8
166 10
6
–
⋅
⋅
⋅
⋅
4 10
6
–
2
0
⋅
⋅
----------------------------------------------------------------
2 8
,
10
9
⋅
=
⋅
=
⋅
=
0 1 2 3 4 5 6 7 8 9 10 11
Absolute distance scale
Intermediate positions can
not be reached.
The user works with these values.
We can see that user resolution is
lower than encoder resolution.
Values are finally divided by 2
K50
to avoid a very big
numerical value for a small motion, because
admitted values should be quickly over passed.
Encoder resolution
K77 determines the encoder
resolution
Содержание DSC Series
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