Siemens SINUMERIK 840D - Page 489

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03.04 Appendix
B Terms
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Ó Siemens AG, 2004. All rights reserved
SINUMERIK 840D/840Di/810D Operator’s Guide HMI Advanced (BAD) – 03.04 Edition A-489
Power ON
The action of switching the control off and then on again.
Preset
The control zero point can be redefined in the machine coordinate
system by means of the Preset function. Preset does not cause the
axes to move; instead, a new position value is entered for the current
axis positions.
Program
1. Control operating area
2. Sequence of instructions to the control system.
Program block
Program blocks contain the main programs and subroutines of the ->
parts programs.
Programmable frames
Programmable -> frames can be used to define new coordinate
system starting points dynamically while the parts program is running.
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 controllers whose
functions are stored as a program in the control unit. The design and
wiring of the unit are not, therefore, dependent on the control
functions. Programmable logic controllers have the same structure as
a computer, i.e. they consist of a CPU with memory, input/output
modules and an internal bus system. The I/Os and programming
language are selected according to the requirements of the control
technology involved.
Programmable working
area limitation
Limitation of the movement area of the tool to within defined,
programmable limits.
Programming key
Characters and character sequences which have a defined meaning
in the programming language for -> parts programs (see
Programming Guide).
Protection zone
Three-dimensional area within a -> working area which the tool tip is
not permitted to enter.
Q
Quadrant error
compensation
Contour errors on quadrant transitions caused by frictional fluctuations
on guideways can be largely eliminated by means of quadrant error
compensation. A circularity test is performed to parameterize the
quadrant error compensation function.