Direction Of Approach To The Target Point With A Rotary Axis - Siemens SIMATIC S5 Manual

Machining Programs and their Structure
Example
N1 O G24 FO
N20G74
N30G24 F5
N40L30
N50G04 F1 O
N60L30
N70G20
N80G20
N90 M02
2.6.6.5

Direction of Approach to the Target Point with a Rotary Axis

With a rotary axis, absolute target points can either be approached by the shortest route (G25)
or clockwise (G26) or anti-clockwise (G27). If machining programs containing these G- functions
are executed on a linear axis, they are ignored.
G25: approach target by shortest route (default at program call)
With a rotary axis, the function G25 means that all absolute targets are approached by the short-
est route. The module itself determines the direction of approach. If the distance to the target is
the same both in a clockwise and anti-clockwise direction, the clockwise direction will always be
selected (= preferred direction). When deciding the direction of approach, backlash compensa-
tion is ignored.
Example
A backlash compensation value was selected in the machine data.
The target is to be approached by the shortest route (G25). The current
position is O degrees.
Ignoring the reversal backlash, the travel distance is the same in both directions.
The direction of the previous job was anti-clockwise.
takes ionger in the preferred direction than in the opposite direction.
0/360 degrees
' —
Backlash \
270
Last traversing movement
Fig. 2/1 8 Reversal backlash with a rotary axis
2 - 3 8
start of a closed loop
approach reference point
start of a loop with 5 repetitions
call subroutine 30
wait one second
recall subroutine 30
end of the inner loop
end of the closed loop
final statement/program end
01360 degrees
'
270
'180
Traversing movement
taking up the backlash
Actual value still at 0/360 degrees
0/360 degrees
180
\
Actual value
Traversing movement
of further 180 degrees
Actual value at 180 degrees
90