Danfoss VLT AutomationDrive FC 301 Programming Manual page 198

Parameter Descriptions
17-76 Position Axis Mode
Option:
[0] Linear
*
Axis
3 3
[1] Rotary 0 -
Max
[2] Rotary
Min -
Max
17-77 Position Feedback Mode
Option:
[0] Relative
*
[1] Absolute The frequency converter uses the absolute
196
Function:
The motion is within a position range defined
by parameter 3-06 Minimum Position and
parameter 3-07 Maximum Position.
Continuous motion, where the position changes
between 0 and parameter 3-07 Maximum
Position. When passing the maximum position,
the reading restarts from 0.
NOTICE
This option is available only with
software version 48.20 and newer.
Continuous motion, where the position changes
between parameter 3-06 Minimum Position and
parameter 3-07 Maximum Position. When passing
the maximum position, the reading restarts from
the minimum position.
Function:
NOTICE
This parameter is only available with
software version 48.2X and newer.
Select the mode for handling absolute encoders.
Select [0] Relative if the application requires to
track the position when the position value
exceeds the measuring range of the encoder, for
example when using single turn encoders for
linear motion. Select [1] Absolute if the position
values are always within the measuring range of
the encoder, for example when using a laser
distance measuring device.
The actual position is set to the absolute position
read from the encoder at power-up, and then the
frequency converter uses only the position
changes for calculating the actual position. In this
mode, the actual position values are between
-2147483648 and 2147483647 even when the
values exceed the measuring range of the
encoder. To save and use the absolute position
values outside the measuring range of the
encoder after power down, set
parameter 17-75 Position Recovery at Power-up to
[1] On. The position value is accurate if the
encoder does not move by more than half of the
encoder measuring range when the frequency
converter is powered down.
position from the encoder as actual position
continuously. In this mode, the actual position
values are between 0 and the maximum position
of the encoder. The maximum position is
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VLT AutomationDrive FC 301/302
17-77 Position Feedback Mode
Option:
3.17.6 17-8* Position Homing
Parameters for configuring the homing function. The
homing function creates a position reference in the
physical machine.
17-80 Homing Function
Option:
[0] No
Homing
*
[1] Home
Position
[2] Home
Sync
Function
[3] Analog
Input 53
Function:
determined by the number of bits, for example,
the SSI encoder has 25 bits and its maximum
value is 2 25 = 33554432. Set
parameter 3-07 Maximum Position to the maximum
value of the encoder scaled according to
parameter 7-94 Position PI Feedback Scale
Numerator, parameter 7-95 Position PI Feebback
Scale Denominator, parameter 17-72 Position Unit
Numerator, and parameter 17-73 Position Unit
Denominator. If the position exceeds the
measuring range of the encoder, the absolute
position reference is lost.
For example, use this option if there is a laser
distance-measuring device and there is a risk that
some external objects may occasionally interfere
with the laser beam. In this case, the absolute
positioning will work correctly when the external
disturbance disappears.
Function:
NOTICE
This parameter is only available with
software version 48.XX.
Select the homing function. The homing
function creates a position reference in the
physical machine. The selected homing function
can be activated with a digital input or a
fieldbus bit. Homing is not required when using
absolute encoders. All homing functions except
[2] Home Sync Function require a start homing
signal.
No homing function. The actual position is 0
after power-up, independent of the physical
machine position.
Actual position is set to the value of
parameter 17-82 Home Position, index 0.
Homing position is synchronized with the
homing sensor according to the setting in
parameter 17-81 Home Sync Function.
Use the value of analog input 53 as the actual
position. The value is scaled according to
parameter 3-06 Minimum Position and
parameter 3-07 Maximum Position.
MG33MO02