HEIDENHAIN TNC 640, User Manual, Page: 147 / 948

Fundamentals, File Management | Fundamentals
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HEIDENHAIN | TNC 640 | Conversational Programming User's Manual | 10/2017
147
Reference systems
For the control to traverse an axis according to a defined path it
requires a
reference system .
A paraxially mounted linear encoder on a machine tool serves
as a simple reference system for linear axes. The linear encoder
represents a
number ray , a unidimensional coordinate system.
To approach a point on the plane , the control requires two axes and
therefore a reference system with two dimensions.
To approach a point in the space , the control requires three axes
and therefore a reference system with three dimensions. If these
three axes are configured perpendicular to each other this creates a
so-called
three-dimensional Cartesian coordinate system .
According to the right-hand rule the fingertips point in
the positive directions of the three main axes.
For a point to be uniquely determined in space, a coordinate origin
is needed in addition to the configuration of the three dimensions.
The common intersection serves as the coordinate origin in a 3-D
coordinate system. This intersection has the coordinates
X+0 , Y+0
and Z+0 .
The control must differentiate between various reference systems
for it to always perform a tool change at the same position for
example, or carry out a machining operation always related to the
current workpiece position.
The control differentiates between the following reference
systems:
Machine coordinate system M-CS:
M achine C oordinate S ystem
Basic coordinate system B-CS:
B asic C oordinate S ystem
Workpiece coordinate system W-CS:
W orkpiece C oordinate S ystem
Working plane coordinate system WPL-CS:
W orking Pl ane C oordinate S ystem
Input coordinate system I-CS:
I nput C oordinate S ystem
Tool coordinate system T-CS:
T ool C oordinate S ystem
All reference systems build up on each other. They are
subject to the kinematic chain of the specific machine
tool.
The machine coordinate system is the reference
system.
X
∆