Siemens SINUMERIK 840D sl Function Manual page 1685

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 subprograms 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. This data
can be initialized directly when it is defined.
Data word
Two-byte data unit within a → data block.
Diagnostics
1. Operating area of the controller.
2. The controller has 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 zero offset in
Automatic mode in conjunction with an electronic handwheel.
Drive
The drive is the unit of the CNC that performs the speed and torque control based on the
settings of the NC.
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.
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
Glossary
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