Programming instructions

4-8
Motion Blocks NC Programming 17VRS
DOK-MTC200-NC**PRO*V17-ANW1-EN-P
ration) is activated automatically. G08 cannot be programmed again
until G61 has been canceled.
•
The G08 function is active with feedrate overrides of 1%–100%. If the
feedrate override is set for more than 100%, the velocity is reduced to
100% in the NC-block transitions.
•
The M-functions stop NC-block execution until an acknowledgment is
received; thus, G08 does not work in NC-blocks in which an M-func-
tion is programmed.
•
After it has been selected, G08 remains active modally until it is can-
celed by G09 or until it is automatically reset at the end of the program
or by BST, M02, M30.
•
Interposed NC-blocks in which no interpolation moves occur do not
cause a velocity change. For example: Interposing a NC-block con-
taining G01 F7000 would cause a speed change.
Note:
The Maximum Feedrate Change w/o Ramp is specified by the
machine builder in the axis parameter Cxx.017.
Examples
The velocity diagram (Fig. 4-10) clearly shows how the NC-block transi-
tion from the first to the second area is traversed at unreduced velocity.
The NC-block transition cannot be detected. In the NC-block transition to
the third section, the feedrate is reduced to F7000. The velocity is re-
duced in an optimal manner to the NC-block starting velocity without
overshooting.
3 Straight Lines X200 --> X0 G06 and G08
Feedrate
Change between
2nd Section and
3rd Section from
F8000 to F7000
Feedrate
-8.0000
Oscilloscope Function
Axis Number: 1
Axis Type: Dig. Linear Axis
Axis Name: X
Process: Master with 4 Axes
Summed Signal Generation
Position Deviation
Actual Position
Fig. 4-10: NC-block transition with G08 and F8000
Example of a program for the velocity diagrams shown in Figs. 4-10 and 4-
11:
G54 G90 G00 G06 G08 X200 Starting point of the X axis
G01 F8000 Feedrate
X150 1st area
X50 2nd area
X0 F7000 3rd area with new F-value
RET Return to program beginning
In the following velocity diagram (Fig. 4-11), the change in velocity between
the second area with F8000 and the third area with F7000 has been magni-
fied using a zoom function. Here one can clearly see the contouring mode
(acceleration) occurring between the two areas.