
5. REFERENCE POSITION
B–63682EN/01
NC FUNCTION
44
In a grid–based reference position return, setting the distance over which
the reference position is to shift in a parameter makes it possible to shift
the reference position without moving a deceleration dog. This function
can greatly reduce the time required in reference position adjustment,
because it is unnecessary to adjust the deceleration dog.
Deceleration
dog
L
DEC
L
SFT
Direction of
reference
position return
Grid point
Machine origin
L
SFT
: Distance over which the reference position is shifted
L
DEC
: Distance to the first grid point (grid point where the distance
over which the reference position is shifted is 0) from a point
where the deceleration dog became off
(L
DEC
is displayed on the diagnosis screen.)
The linear scale with absolute addressing reference marks has reference
marks (one–rotation signals) at intervals that change at a constant rate.
By determining the reference mark interval, the corresponding absolute
position can be deduced. The CNC makes a small movement along an
axis to measure the one–rotation signal interval, then calculates the
absolute position. The reference position can be established without
performing positioning to the reference position.
Reference
mark 1
Reference
mark 2
Reference
mark 1
Reference
mark 2
Reference
mark 1
10.02
10.04
20.02
20.00
20.00
10.06
Fig. 5.5 Sample linear scale with absolute addressing reference marks
5.4
REFERENCE POINT
SHIFT
5.5
LINEAR SCALE WITH
ABSOLUTE
ADDRESSING
REFERENCE MARKS