Siemens sinumerik 840D sl Function Manual page 210

Detailed description
2.2 Programmable contour accuracy
Activating
The monitoring will only become active if the following conditions are met:
• The contour tunnel monitoring function is set.
• MD21050 is higher than 0.0.
• At least two geometry axes have been defined.
Stopping
Monitoring can be stopped by enabling the MD setting:
MD21050 = 0.0.
Analysis output
The values of deviation of the actual value of the tool tip from the programmed path can for
analysis purposes be output on a fast analogue output (accuracy monitoring).
The parameter assignment is activated with machine data:
MD21070 $MC_CONTOUR_ASSIGN_FASTOUT
(Assignment of an analog output for output of the contour error)
Value
0
1
2
..
8
Scale
The tunnel radius set in MD21050 corresponds to a voltage of 10 V at the output.
2.2 Programmable contour accuracy
Initial situation
There is always a velocity-dependent difference between setpoint and actual position when
an axis is traversed without feedforward control. This lag results in inaccurate curved
contours.
References:
/FB1/Function Manual Basic Functions
/PG/ Programming Manual Fundamentals
8
Meaning
No output (default setting)
Output to output 1
Output to output 2
..
Output to output 8
Special functions: Contour Tunnel Monitoring (K6)
Function Manual, 11/2006, 6FC5397-2BP10-2BA0