Allen-Bradley 1747-PBASE, Programming Manual

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Publication 1746-PM001A-US-P
6-10 Writing Programs Using the BASIC Development Language
Subprogram CALL 70, CALL 71
In a main program, the BASIC commands CALL 70 and CALL 71 cause execution
to branch to a subprogram. The subprogram must have been previously stored in
the memory module of the BASIC or BASIC-T module. Execution can be
returned to the main program with a CALL 72. Refer to the
BASIC Language
Reference Manual (publication number 1746-RM001A-US-P) or the SLC 500™
BASIC and BASIC-T Module User Manual (publication number
1746-UM004A-US-P).
Programming Macros
Appendix A describes the programming macros contained in the BASIC
Development Software. Programming macros are BASIC subroutines that can be
used through the BASIC development language. You can also create your own
programming macros using the $Macro translator directive described in this
chapter.
Merging a Program File
There are two ways to merge program files: the
$Include
translator directive and
the
Merge file from disk
option available from the File menu.
$Include
can
be used only with BASIC development language programs and is described in this
chapter in the translator directives section.
Merge file from disk
can be used with any program file. It prompts you for a
filename and then merges that file into your program at the current cursor location.
IMPORTANT
The BASIC and BASIC-T modules do not distinguish between
subprogram variables and main program variables. If a variable
used in the main program is changed in a subprogram, the main
program is affected.
IMPORTANT
If you merge two .BAS files with any identical line numbers, the
duplicate line numbers remain until you download the file to the
module. At that time, if there is more than one line of the same
number, the last line downloaded replaces any preceding lines
with that number. This is not a problem with .BDL files, since
line numbering is not allowed.