Siemens sinumerik 840D sl Function Manual page 213

Restrictions
Coupled motion
If coupled motion between two geometry axes is programmed with contour tunnel
monitoring, this always results in activation of the contour tunnel monitoring.
In this case, the contour tunnel monitoring must be switched off before programming the
coupled motion:
MD21050 $MC_CONTOUR_TUNNEL_TOL = 0.0
Special functions: Contour Tunnel Monitoring (K6)
Function Manual, 11/2006, 6FC5397-2BP10-2BA0
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