Special cases

Special case 1: Look Ahead range overflow

Large number of blocks between START – END

The Look Ahead range comprises a maximum of 20 NC blocks. Lifting is executed prematurely if the range of the motion path (Look Ahead range) considered during lifting is fully occupied due to a large number of blocks. In this case, the axis is first lifted to the specified maximum height and lowered shortly before END (see blue curve in the figure)..

Premature lifting can lead to a situation where less motion path is available for the lifting motion than the user actually assumes. As a result, path velocity may be reduced in order to execute the lifting motion and re-engagement.

Conclusion: A high number of blocks between lift start and end leads to premature lifting of the lift axis and to a possible deceleration of the path motion. For this reason Advanced Lifting is recommended.

Diagram of Look Ahead range overflow
Diagram of Look Ahead range overflow

Programing Example

prg_example

Look Ahead range overflow

N10 Z10

N20 Z[LIFT_START POS_LIMIT=30]

N30 X10

N40 X20

N50 X35

...

N550 X31

N560 X32

N570 X33

N580 X34

N600 Z[LIFT_END]

Special case 2: Lifting and explicit flushing of the channel

LIFT and flushing the channel (#FLUSH)

During lifting, the motion blocks are first stored to enable calculation of the optimum lifting motion from LIFT start to end. With various NC commands, however, immediate execution is necessary and this is achieved implicitly by "flushing the channel".

If channel output of the NC blocks is forced during lifting (e.g. NC command #FLUSH), the lifting motion is executed as if LIFT_END and a repeated LIFT_START were programmed at this point.

Programing Example

prg_example

Lifting and explicit flushing of the channel

N20 X40 Z2

N30 Z[LIFT_START POS=12 POS_LIMIT=40]

N40 X50

N50 X40

N60 #FLUSH

N70 X30

N80 X20

N90 Z[LIFT_END]

Operating principle of #FLUSH with comparable programming

N20 X40 Z2

N30 Z[LIFT_START POS=40 POS_LIMIT=40]

N40 X50

N50 X40

N60 Z[LIFT_END]

N60 Z[LIFT_START POS=12 POS_LIMIT=40]

N70 X30

N80 X20

N90 Z[LIFT_END]