Siemens SINUMERIK 808D User Manual page 107

See the following illustration for exact stop window coarse or fine, in effect for G60/G9:
Programming example
N5 G602
N10 G0 G60 X20
N20 X30 Y30
N30 G1 G601 X50 Y50 F100
N40 G64 X70 Y60
N50 G0 X90 Y90
N60 G0 G9 X95
N70 G0 X100 Y100
M30
N o te
The G9 command only generates exact stop for the block in which it is programmed; G60, however, is effective until it is
canceled by G64.
C o ntinuous-path control mode G64
The objective of the continuous-path control mode is to avoid deceleration at the block boundaries and to switch to the next
b l ock with a path velocity as constant as possible (in the case of tangential transitions). The function works with l o ok-ahead
ve locity control over several blocks.
For non-tangential transitions (corners), the velocity can be reduced rapidly enough so that the axes are subject to a
relatively high velocity change over a short period of time. This may lead to a significant jerk (acceleration change). The size
of the jerk can be limited by activating the SOFT function.
Programming example
N10 G64 G1 X10 Y20 F1000
N20 X30 Y30
N30 G60 Z50
M30
L o ok-ahead velocity control:
In the continuous-path control mode with G64, the control system determines the velocity control for several NC blocks in
advance automatically. This enables acceleration and deceleration across multiple blocks with approximately tangential
transitions. For paths that consist of short travels in the NC blocks, higher velocities can be achieved than without look
ahead.
Programming and Operating Manual (Milling)
6FC5398-4DP10-0BA6, 09/2017
; Exact stop window coarse
; Exact stop modal
; G60 continues to act
; Exact stop window fine
; Switching over to continuous-path mode
; Exact stop acts only in this block
; Again continuous-path mode
; Continuous-path mode
; Continuous-path control mode continues to be active
; Switching over to exact stop
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