Siemens Sinumerik 840D sl Programming Manual page 211

User memory
All programs and data, such as part programs, subprograms, comments, tool offsets, work
offsets/frames, as well as channel and program user data, can be stored in the shared CNC
user memory.
User-defined variables
Users have the option of defining variables for their own purposes in the -> part program or
in a data block (global user data). The variable definition contains the specification of the
data type and the variable name. See also -> System variable.
Variable definition
A variable is defined by specifying a data type and a variable name. The variable name can
be used to access the value of the variable.
Velocity control
The control system can execute a look-ahead evaluation over several blocks (-> LookAhead)
to achieve an acceptable traversing speed during movements that require only very small
adjustments of position in a block.
Vocabulary words
Words with a certain notation and a defined meaning in the programming language for ->
part programs.
Work memory
The work memory is a memory offering free access (RAM or Random Access Memory) in
the -> CPU which the processor accesses while executing the application program.
Work offset
Specification of a new reference point for a coordinate system by referring to an existing zero
point and a -> Frame.
1. Adjustable
SINUMERIK 840D: There is a parameterizable number of adjustable work offsets for each
CNC axis. Each work offset can be selected via G functions; the selection is exclusive.
2. External
All movements that define the position of the workpiece zero can be superimposed by an
external work offset, which
is either defined by a handwheel (DRF movement) or
the PLC.
3. Programmable
The TRANS instruction can be used to program work offsets for all path and positioning
axes.
ISO Milling
Programming Manual, 06/09, 6FC5398-7BP10-1BA0
Glossary
211