Siemens sinumerik 840D sl Function Manual page 209

Detailed description
2.1 Contour tunnel monitoring
Aim of the monitoring function
The aim of the monitoring function is to stop the movement of the axes if axis deviation
causes the distance between the tool tip (actual value) and the programmed path (setpoint)
to exceed a defined value (tunnel radius).
Tunnel size
The radius of the contour tunnel being monitored around the programmed path must be
defined to implement the monitoring function.
The radius is set in the machine data:
MD21050 $MC_CONTOUR_TUNNEL_TOL (Response threshold for Contour tunnel
monitoring)
If the machine data is set to 0.0, monitoring is not performed. The value of the machine data
is transferred to the control for new configurations.
Parameterizable deceleration behavior
The deceleration behavior for the monitoring response can be set via the following machine
data:
MD21060 $MC_CONTOUR_TUNNEL_REACTION
(Reaction upon response of contour tunnel monitoring)
Value
0
1
2
Encoder switchover
Switching between two encoder systems usually causes a sudden change in the actual
position of the tool tip. This change resulting from encoder switchover must not be so large
as to cause the tool tip to violate the monitoring tunnel. The radius defined in MD21050 must
be higher than the allowed tolerance on actual value switchover:
MD36500 $MA_ENC_CHANGE_TOL (Tolerance on position actual value switchover)
Special functions: Contour Tunnel Monitoring (K6)
Function Manual, 11/2006, 6FC5397-2BP10-2BA0
Meaning
Display alarm and continue machining
Deceleration according to the deceleration ramps (default setting)
Rapid stop (speed setpoint = 0)
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