Siemens SINUMERIK 840D sl Programming Manual page 920

Glossary
CPU
Central processing unit, see → PLC
C-Spline
The C-Spline is the most well-known and widely used spline. The transitions at the
interpolation points are continuous, both tangentially and in terms of curvature. 3rd order
polynomials are used.
Curvature
The curvature k of a contour is the inverse of radius r of the nestling circle in a contour point
(k = 1/r).
Cycles
Protected subroutines for execution of repetitive machining operations on the → workpiece.
Data block
1. Data unit of the → PLC that → HIGHSTEP programs can access.
2. Data unit of the → NC: Data modules contain data definitions for global user data. These
Data word
Two-byte data unit within a → data block.
Diagnosis
1. Operating area of the control.
2. The control has both a self-diagnostics program as well as test functions for servicing
Dimensions specification, metric and inches
Position and lead values can be programmed in inches in the machining program.
Irrespective of the programmable dimensions (G70/G71), the controller is set to a basic
system.
920
data can be initialized directly when they are defined.
purposes: status, alarm, and service displays
Programming Manual, 06/2009, 6FC5398-2BP20-0BA0
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