12 Functional Descriptions 12.93
12.12.5 Influence of the modes on the path dimension function from the PLC
Comments:
• Keys/switches on the machine control panel:
Direction keys, rapid traverse overlay, axis selector switch have no effect.
• Feedrate override switch:
The switch position 0% is always active for path dimension, irrespective of the setting of
the PLC interface signal ”Feedrate not active”.
• Program control:
Dry run feedrate and rapid traverse override are not active.
• Facing axis function as a diameter:
If the path dimension axis selected is a facing axis, the facing axis functions usual in the
NC apply. If diameter incremental dimensioning is selected, the path dimension along
which the facing axis has to traverse is halved. (MD bit: INC/DRF/handwheel: facing axis
functin in diameter).
• Rotary axis traversing functions:
If the selected path axis is a rotary axis, then the usual NC rotary axis traversing functions
such as modulo programming for rotary axes and actual value display modulo 360 degrees
apply. The path dimension to be traversed is evaluated by division into degrees according
to the selected input resolution.
On an NC start after a block search with calculation after a rotary axis path dimension, the
calculated distance to go is projected within a range of -180° < distance to go < 180°.
On NC start after automatic interrupt, the complete distance to the part program block end
point is traversed!
• Indexing axis
If an axis is an indexing axis, the path dimension is not interpreted as a division number.
The path dimension is traversed as specified.
• Handwheel mode
Handwheel mode can be active while a path dimension is being traversed (overlay). If you
do not want this, you can deselect the handwheel in the machine data or with a PLC
interface signal.
• Preset/DRF offset
The actual value offset DRF and preset apply to the absolute axis actual value.
When the path dimension axis is traversed to an absolute position, the DRF and PRESET
offset are not included in the calculation.
• Rounding axis
No rounding logic is performed! If the path dimension axis is a rounding axis, the path
dimension must be a multiple of the rounding position. (Dealt with as in the part program).
A check is made to see whether an incorrect position was given. The path dimension is
aborted to prevent an incorrect position from being traversed. (Negative acknowledgement
with error/number to the PLC).
12–100
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SINUMERIK 840C (IA)