Siemens SINUMERIK 840D sl, Function Manual

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Glossary
Basic logic functions: Appendix
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
21
CPU
Central processing unit, see → Memory-programmable control
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.
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.
Diagnose
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 pitch 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.
DRF
Differential Resolver Function: NC function which generates an incremental work offset in
Automatic mode in conjunction with an electronic handwheel.
Drive
The SINUMERIK 840D control system is digitally connected to the SIMODRIVE 611
converter system over a high-speed digital parallel bus.
Dynamic feedforward control
Inaccuracies in the → contour due to following errors can be practically eliminated using
dynamic, acceleration-dependent feedforward control. This results in excellent machining
accuracy even at high → path velocities. Feedforward control can be selected and
deselected on an axis-specific basis via the → part program.