Danfoss VLT AutomationDrive FC 301 Programming Manual page 588

Programming Guide | VLT® AutomationDrive FC 301/FC 302
Option Name
[0]* Relative
[1] Absolute
17-78 Active Position Counter
Default value: [0] Counter 0
Setup:
All setups
Data type: Uint8
The drive has 4 individual position counters. Only the selected counter is updated. Allows tracking position of up to 4 motors controlled
by 1 drive, 1 motor at a time. The active counter can be selected by this parameter in the same setup or by setup change when selecting
between motors.
Option Name
[0]* Counter 0
[1] Counter 1
[2] Counter 2
[3] Counter 3
588 | © 2024.09
Description
The actual position is set to the absolute position read from
the encoder at power-up, and then the drive 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 drive is
powered down.
The drive uses the absolute 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 determined by the number of bits, for
example, the SSI encoder has 25 bits and its maximum value is
25
2 = 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 Feedback 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.
Parameter type:
Conversion index:
Change during operation:
Description
Parameter Descriptions
Option
–
False
AU275636650261en-003201 / 130R0334