Siemens SINUMERIK 840D sl Function Manual page 1114

Glossary
Programmable Logic Control
Programmable logic controllers (PLC) are electronic controls, the function of which is stored
as a program in the control unit. This means that the layout and wiring of the device do not
depend on the function of the control. The programmable logic controller has the same
structure as a computer; it consists of a CPU (central module) with memory, input/output
modules and an internal bus system. The peripherals and the programming language are
matched to the requirements of the control technology.
Programmable working area limitation
Limitation of the motion space of the tool to a space defined by programmed limitations.
Programming key
Character and character strings that have a defined meaning in the programming language
for → part programs.
Protection zone
Three-dimensional zone within the → working area into which the tool tip must not pass.
Quadrant error compensation
Contour errors at quadrant transitions, which arise as a result of changing friction conditions
on the guideways, can be virtually entirely eliminated with the quadrant error compensation.
Parameterization of the quadrant error compensation is performed by means of a circuit test.
R parameters
Arithmetic parameter that can be set or queried by the programmer of the → part program for
any purpose in the program.
Rapid traverse
The highest traverse rate of an axis. For example, rapid traverse is used when the tool
approaches the → workpiece contour from a resting position or when the tool is retracted
from the workpiece contour. The rapid traverse velocity is set on a machine-specific basis
using a machine data element.
Reference point
Machine tool position that the measuring system of the → machine axes references.
Rotary axis
Rotary axes apply a workpiece or tool rotation to a defined angular position.
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Function Manual, 09/2009, 6FC5397-1BP20-0BA0
Extended Functions