Siemens SINUMERIK 840Di sl Programming Manual page 62

Fundamental Principles of NC Programming
2.2 Language elements of the programming language
Note
Number of characters for each identifier
• Program names: 24 characters
• Axis identifiers: 8 characters
• Variable identifiers: 31 characters
Rules for allocating identifiers
The following rules are provided in order to avoid identifier collisions:
• All identifiers beginning with "CYCLE" or "_" are reserved for SIEMENS cycles.
• All identifiers beginning with "CCS" are reserved for SIEMENS compile cycles.
• User compile cycles begin with "CC".
• We recommend that users select identifier names, which either begin with "U" (User) or
Further reserved identifiers
• The identifier "RL" is reserved for conventional turning machines.
• All identifiers beginning with "E_ " are reserved for EASY-STEP programming.
Variable identifiers
In variables used by the system, the first letter is replaced by the "$" character. This
character may not be used for user-defined variables.
Examples (see "List of system variables"):
$P_IFRAME, $P_F
Leading zeroes are ignored in variables with numeric extensions (i.e., R01 is interpreted as
R1). Separators are allowed before a numeric extension.
Array identifiers
The rules for elementary variables also apply to array identifiers. It is possible to address
arithmetic variables as arrays.
Example:
R[10]=...
Data types
A variable can contain a numeric value (or several) or a character (or several), e.g., an
address letter.
62
contain the underscore symbol, because these are not used by the system, compile
cycles or SIEMENS cycles.
Programming Manual, 11/2006, 6FC5398-1BP10-2BA0
Fundamentals