Siemens Sinumerik 840D sl Programming Manual page 913

Coordinate system
See → Machine coordinate system, → Workpiece coordinate system
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 can be initialized directly when they are defined.
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
purposes: status, alarm, and service displays
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.
Job planning
Programming Manual, 02/2011, 6FC5398-2BP40-1BA0
Glossary
913