
B-65270EN/05 2. SETTING αiS/αiF/βiS SERIES SERVO PARAMETERS
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(9) Reference counter setting
Specify the reference counter.
The reference counter is used in making a return to the reference
position by a grid method.
(a) Semi-closed loop
Count on the reference
counter
=
Number of position pulses corresponding to a
single motor revolution or the same number
divided by an integer value
NOTE
If the motor-table rotation ratio for a rotation axis is
not an integer, it is necessary to set the reference
counter capacity in such a way that points where
reference counter = 0 (grid points) appears always
at the same position for the table.
Example of setting
αi Pulsecoder and semi-closed loop (1-µm detection)
Ball screw lead
(mm/revolution)
Necessary number of
position pulses
(pulse/revolution)
Reference
counter
Grid width
(mm)
10
20
30
10000
20000
30000
10000
20000
30000
10
20
30
When the number of position pulses corresponding to a single motor
revolution does not agree with the reference counter setting, the
position of the zero point depends on the start point.
In such a case, set the reference counter capacity with a fraction to
change the detection unit and eliminate the error in the reference
counter. (Except Series 9096)
Example of setting
System using a detection unit of 1 µm, a ball screw lead of 20
mm/revolution, and a gear reduction ratio of 1/17
(a)-1 Method of specifying the reference counter capacity with a fraction (except
Series 9096)
The number of position pulses necessary for the motor to make one
turn is: 20000/17
Set the following parameter as stated below.
1896 (FS15i)
Reference counter capacity (numerator)
1821 (FS30i, 16i)
[Valid data range] 0 to 99999999
Set the numerator of a fraction for the reference counter capacity.