Siemens SINUMERIK 840D sl Function Manual page 223

Restrictions
The following restrictions apply when programming:
• The NC block must not generate a preprocessing stop.
• No discontinuities may occur in leading axis motion.
• Any block that contains a traverse instruction for the following axis must also include a
traverse for the leading axis.
• The direction of motion of the leading axis must not reverse at any point in the rule of
motion, i.e. the position of the leading axis must always be unique within the sequence of
motions.
The programmed contour may not move perpendicular to the leading axis.
• Axis names from gantry axis groups cannot be used to define a table (only leading axis are
possible).
• Depending on the following machine data, jumps in the following axis may be tolerated if a
movement is missing in the leading axis.
MD20900 $MC_CTAB_ENABLE_NO_LEADMOTION (curve tables with discontinuity of
the following axis)
The other restrictions listed above still apply.
Axis assignment
Does not take effect until coupling is activated with curve table.
Note
The dynamic limit values of the motion commands for a curve table are not checked until
activation or interpolation.
Starting value
The first motion command in the definition of a curve table defines the starting value for the
leading and following value.
All instructions that cause a preprocessing stop must be removed.
Example 1
Without tool radius compensation, without memory type
N100 CTABDEF(AX2, AX1, 3,0)
N110 AX1=0 AX2=0
N110 AX1=20 AX2=0
N120 AX1=100 AX2=6
Special Functions
Function Manual, 09/2011, 6FC5397-2BP40-2BA0
; Beginning of the definition of non-
; periodic curve table No. 3
; 1. Motion instruction specifies the start value
; master value: 0, Following value: 0
; 1. Curve segment: Master value: 0...20, Following
value: Starting value ...0
; 2. Curve segment: Master value: 20...100,
following value: 0...6
M3: Coupled axes
5.2 Curve tables
223