Flexible Nc Programming; Variables; System Variable - Siemens SINUMERIK 840D sl Programming Manual

Flexible NC programming

1.1

Variables

The use of variables, especially in conjunction with arithmetic functions and check structures,
enables part programs and cycles to be set up with extremely high levels of flexibility. The
system provides three different types of variables.
● System variables
● User variables
1.1.1

System variable

System variables are variables which are predefined in the system and enable access to the
current parameter settings of the control, as well as to machine, control, and process states,
in part programs and cycles.
Job Planning
Programming Manual, 03/2013, 6FC5398-2BP40-3BA1
System variables are variables with a fixed predefined meaning; they are defined in the
system and made available to the user. They are also read and written by the system
software. Example: Machine data
The meaning of a system variable is permanently set by the system. However, minor
modifications can be made to the properties by the user in the form of redefinition. See
"Redefinition of system variables, user variables, and NC language commands (REDEF)
(Page 29)"
User variables are variables whose meaning is not known to the system; they are not
evaluated by the system. The meaning is defined exclusively by the user.
User variables are subdivided into:
– Predefined user variables
Predefined user variables are variables which have already been defined in the
system and whose number simply has to be parameterized by the user via specific
machine data. The user can make significant changes to the properties of these
variables. See "Redefinition of system variables, user variables, and NC language
commands (REDEF) (Page 29)".
– User-defined variables
User-defined variables are variables which are defined exclusively by the user and are
not created by the system until runtime. Their number, data type, visibility, and all
other properties are defined exclusively by the user.
See "Definition of user variables (DEF) (Page 24)"
1
17