Siemens SINUMERIK 840Di Function Manual page 2039

Programmable frames
Programmable → frames enable dynamic definition of new coordinate system output points
while the part program is being executed. A distinction is made between absolute definition
using a new frame and additive definition with reference to an existing starting point.
Programmable Logic Controller
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 largely eliminated using quadrant error compensation. Quadrant
error compensation is parameterized by a circularity test.
RAM
RAM is a work memory in the → CPU that the processor accesses when processing the user
program.
Rapid traverse
Maximum 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.
Raw part
Workpiece as it is before it is machined.
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
Glossary
Glossary-15