Tormach PCNC 770 - Page 116

Chapter 7
116
UM10350_PCNC770_Manual_0916A
Programming
Rotaonal axis (A-axis) words are allowed in canned cycles, but it is beer to omit them. If rotaonal
axis words are used, the numbers must be the same as the current posion numbers so that the
rotaonal axes do not move.
The R number is always scky. Scky numbers keep their value on subsequent blocks if they are not
explicitly programmed to be dierent.
In absolute distance mode (G90), the X, Y, R and Z numbers are absolute posions in the current
coordinate system. In incremental distance mode (G91), when the XY-plane is selected, X, Y, and R
numbers are treated as increments to the current posion and Z as an increment from the Z-axis
posion before the move involving Z takes place; when the YZ- or XZ-plane is selected, treatment
of the axis words is analogous.
Many canned cycles use the L word. The L word is oponal and represents the number of repeats.
L0 is not allowed. The L word is not scky. The interpretaon of the L word depends on the acve
distance mode:
• In incremental distance mode (G91), L > 1 in incremental mode means (with the XY-plane
selected), that the X and Y posions are determined by adding the given X and Y numbers
either to the current X and Y posions (on the rst iteraon) or to the X and Y posions at the
end of the previous go-around (on the subsequent repeons). The R and Z posions do not
change during the repeats
• In absolute distance mode (G90), L > 1 means do the same cycle in the same place several
mes. Oming the L word is equivalent to specifying L=1
The height of the retract move at the end of each repeat (called clear Z in the descripons below) is
determined by the seng of the retract mode: either to the original Z posion (if that is above the
R posion and the retract mode is G98) or otherwise to the R posion.
It is an error if:
• X, Y, and Z words are all missing during a canned cycle
• A P number is required and a negave P number is used
• An L number is used that does not evaluate to a posive integer
• Rotaonal axis moon is used during a canned cycle
• Inverse me feed rate is acve during a canned cycle
• Cuer radius compensaon is acve during a canned cycle
When the XY plane is acve, the Z number is scky and it is an error if:
• The Z number is missing and the same canned cycle was not already acve
• The R number is less than the Z number