
4.REFERENCE POSITION ESTABLISHMENT B-63943EN-1/02
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4.7 DISTANCE CODED LINEAR SCALE INTERFACE
Overview
The interval of each reference marks of distance coded linear scale are
variable. Accordingly, if the interval is determined, the absolute
position can be determined. The CNC measures the interval of
reference marks by axis moving of short distance and determines the
absolute position. Consequently the reference position can be
established without moving to reference position.
10.02
10.04
20.02
20.00
20.00
Reference mark 1 Reference mark 2Mark 1 Mark 2 Mark 1
Fig.4.7(a) Example of distance coded linear scale
NOTE
This is an optional function.
Procedure for reference position establishment
- Procedure
(1) Select the JOG mode, and set the manual reference position
return selection signal ZRN to "1".
(2) Set a direction selection signal(+J1,-J1,+J2,-J2,…) for a target
axis.
(3) The axis is fed at a constant low speed (reference position return
FL feedrate specified by parameter (No.1425) setting).
(4) When a reference mark is detected, the axis stops, then the axis is
fed at a constant low speed again.
(5) Above (4) is executed repeatedly until two, three or four
reference marks are detected. And absolute position is
determined and reference position establishment signal
(ZRF1,ZRF2,ZRF3, …) turns to "1".
(A number of reference marks is determined by the parameter
No.1802#2, #1. )
Even when the direction selection signal (+J1, -J1, +J2, -J2,...) is set to
"0" while steps (2) to (5) are being performed, the feedrate operation
does not stop, and the operation for establishing a reference position is
carried out continuously.