Danfoss MCO 305 Design Manual page 205

MCO 305 Design Guide
All path information in motion commands are made
in user units and are converted to quad-counts
internally. By choosing these scaling units corres-
pondingly it is possible to work with any technical
measurement unit (for example mm).
This factor is a fraction which consists of a numera-
tor and denominator.
par. 32 -
1 User Unit UU =
par. 32 -
Scaling determines how many quad-counts make
up a user unit.
In CAM-Mode, the parameter is used to fix the unit
for the slave drive so that it is possible to work
with meaningful units in the CAM-Editor. See
example 2.
Gearing Factor ∗ Encoder
Scaling Factor
provided that:
Gearing Factor
Encoder = Incremental encoder (in the case
of absolute encoders, the multi-
plier 4 is omitted)
Scaling factor = Number of user units UU (qc)
that correspond to one revolution
at the drive
In addition, it is possible to compress or expand
the curves with this factor without having to define
new curves each time. The use of numerator and
denominator for the gearing factor leads to a very
precise result since transmission ratios can be re-
presented as a fraction in virtually all cases.
The factor is no longer limited to small values
starting with version MCO 5.00, see also User
Units.
Example 1
Shaft or spindle
25 motor revolutions result in 1 spindle revolution;
gearing factor = 25/1
Encoder resolution (incremental encoder) = 500
Spindle gradient = 1 revolution of the spindle =
5 mm
Scaling factor in case of working with 1/10 mm
resolution = 5 * 10 = 50
25
∗ 500 ∗ 4
25 ∗ 10 ∗ 4
1
qc =
50 1
Par. 32-12 User Unit Numerator
Par. 32-11 User Unit Denominator
default setting
__ Parameter Reference __
12 User Unit Numerator
11 User Unit Denomintor
Resolution ∗ 4
qc = 1 UU
Motor Revolution s
=
Revolution s on Output
1000
qc = qc = 1 UU
1
= 1000
= 1
[ ] value for use in communication via serial communication port
®
MG.33.L5.02 – VLT
Example 2
Cylinder:
Gear factor = 5/1
Encoder resolution (incremental encoder) = 500
One revolution of the cylinder is 360 degrees. It is
requested to work with a resolution of 1/10
degrees. This means that one revolution of the
cylinder is divided into 3600 units.
Scaling factor = 3600
5/1 ∗ 500 ∗ 4 5
qc =
3600
25 par.
= qc = 1 UU =
9 par.
par. 32-12 User Unit Numerator
par. 32-11 User Unit Denominator
The factor is no longer limited to small values
starting with version MCO 5.00, see also User Units
in chapter „How to read the Design Guide".
32-13 Enc.2 Control
ENCCONTROL - 107
Option
No soft changing
Encoder soft changing enable
Soft zero setting enable
Encoder soft changing and soft zero
enable
Function
The Encoder Control Word configures the position
evaluation after a change of encoder source.
Soft encoder changing is useful if encoders should
be switched while running. If this is done without
using this parameter, then setting the new encoder
will typically cause a position error because the
encoder values are not the same.
Select No soft changing [0] to switch directly to the
position data of the new source.
Select Encoder soft changing [1] not to switch
entirely to the value of the new encoder. Instead,
the old value is kept and the differences from the
new encoder is just added. This makes it possible
to change encoders "on the run".
is a registered Danfoss trademark
∗ 500 ∗ 4
qc = 1 UU
3600
32 - 12 User Unit Numerator
32 - 11 User Unit Denomintor
= 25
= 9
[0]
[1]
[2]
[3]
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