Main Run Variables For Synchronized Actions; General Information On System Variables - Siemens SINUMERIK 840D sl Programming Manual

10.3

Main run variables for synchronized actions

10.3
10.3.1

General information on system variables

Function
NC data can be read and written with the help of system variables. A distinction is made
between preprocessing and main run system variables. Preprocessing variables are always
executed at the preprocessing time. Main run variables always calculate their value with
reference to the current main run status.
Syntax of system variables
System variable names always begin with a "$" sign.
Preprocessing variables:
• $M... , machine data
• $S... , setting data, protection zones
• $T... , tool management data
• $P... , programmed values, preprocessing data
• $C... , cycle variables of the ISO wrapper cycles
• $O... , options data
• R... , R parameter
Main run variables:
• $A... , current main run data
• $V... , servo data
• $R... , R parameter
a 2nd letter describes options for accessing the variable:
• N... , NCK global value (generally valid value)
• C... , channel-specific value
• A... , axis-specific value
The 2nd letter is usually only used for main run variables. Preprocessing variables, such as
$P_, are usually executed without the 2nd letter.
An underscore and the subsequent variable name, usually an English designation or
abbreviation, follow the prefix ($ followed by one or two letters).
Job planning
Programming Manual, 03/2006 Edition, 6FC5398-2BP10-1BA0
Motion synchronous actions
10.3 Main run variables for synchronized actions
10-9