Function Call Isvar And Read Machine Data Array Index - Siemens Sinumerik 840D sl Programming Manual

14.6

Function call ISVAR and read machine data array index

Function
The ISVAR command is a function as defined in the NC language that has a
• Function value of type BOOL
• transfer parameter of type STRING
The ISVAR command returns TRUE if the transfer parameter contains a variable known in
the NC (machine data, setting data, system variable, general variables such as GUDs).
Syntax
ISVAR(<variable identifier>)
ISVAR(<identifier>,[<value>,<value>])
Significance
<Variable identifier>
<identifier>
<value>
Checks
The following checks are made in accordance with the transfer parameter:
• Does the identifier exist
• Is it a 1- or 2-dimensional array
• Is an array index permitted
Only if all these checks have a positive result will TRUE be returned. If a check has a negative
result or if a syntax error has occurred, it will return FALSE. Axial variables are accepted as
an index for the axis names but not checked.
Extension: Read machine data and setting data array without index.
If there is no index for general and channel-specific machine data, alarm 12400 "channel % 1
block % 2 array % 3 element not present" is no longer output.
At least the axis index must still be programmed for axis-specific machine data. Otherwise
alarm 12400 will be issued.
Job planning
Programming Manual, 02/2011, 6FC5398-2BP40-1BA0
14.6 Function call ISVAR and read machine data array index
Transfer parameter of type string can be undimensioned,
1-dimensional, or 2-dimensional.
Identifier with a known variable with or without an array
index as machine data, setting data, system variable, or
general variable.
Extension:
For general and channel-specific machine data, the first
element of the array will be read even when no index is
specified.
Function value of type BOOL
Additional functions
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