Limit Angle - Siemens SINUMERIK 840D sl Function Manual

8.4

Limit angle

Description of problem
When the axis moves backwards and forwards along the path, the tangent turns abruptly
through 180 degrees at the path reversal point. This response is not generally desirable for
this type of machining operation (e.g. grinding of a contour). It is far better for the reverse
motion to be executed at the same offset angle (negative) as the forward motion.
Figure 8-3
Programming
A minimum and a maximum value for the position of the axis made to follow ("C" in example)
referred to the base coordinate system are transferred to the control with G25 and G26. These
working area limitations are activated with WALIMON and deactivated again with WALIMOF.
The working area limitation must be active at the instant of path reversal.
References:
/PG/Programming Manual Fundamentals
Activation
If the current offset angle is outside the active working area limit for the following axis, an
attempt is made to return to within the permissible working area by means of the negative
offset angle. This response corresponds to that shown in the lower diagram of the above Fig.
Special Functions
Function Manual, 09/2011, 6FC5397-2BP40-2BA0
Backward and forward motion on the path
T3: Tangential control
8.4 Limit angle
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