Siemens sinumerik 840D sl Function Manual page 967

Glossary
User Program
User programs for the S7-300 automation systems are created using the programming
language STEP 7. The user program has a modular layout and consists of individual blocks.
The basic block types are:
• Code blocks
• Data blocks
User-defined variable
Users can declare their own variables for any purpose in the → part program or data block
(global user data). A definition contains a data type specification and the variable name. See
→ System variable.
Variable definition
A variable definition includes the specification of a data type and a variable name. The
variable names can be used to access the value of the variables.
Velocity control
In order to achieve an acceptable traverse rate in the case of very slight motions per block,
an anticipatory evaluation over several blocks (→ Look Ahead) can be specified.
Working area
Three-dimensional zone into which the tool tip can be moved on account of the physical
design of the machine tool. See → Protection zone.
Working area limitation
With the aid of the working area limitation, the traversing range of the axes can be further
restricted in addition to the limit switches. One value pair per axis may be used to describe
the protected working area.
Working memory
RAM is a work memory in the → CPU that the processor accesses when processing the
application program.
Workpiece
Part to be made/machined by the machine tool.
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These blocks contain the STEP 7 commands.
These blocks contain constants and variables for the STEP 7 program.
Special functions: Appendix
Function Manual, 11/2006, 6FC5397-2BP10-2BA0