Rockwell Automation 1746-BAS BASIC LANGUAGE - Manual (Page 134)

Publication 1746-RM001A-US-P
11-4 Status Functions
CALL 55 – Check CPU
Input Image Buffer Purpose
Use CALL 55 to determine if the SLC 500 controller input image buffer located in
the module has been read by the Logic Processor since the last time it was checked.
This routine has no input arguments and one output argument.
The output argument is equal to:
•
0 – if the Logic Processor has not read from the input image buffer since the
last time the CALL was executed or since the module was powered up,
whichever occurred last
•
1 – if the Logic Processor has read from the input image buffer since the last
time this CALL was executed or since the module was powered up, whichever
occurred last
•
2 – if a Logic Processor does not support this capability (as with the SLC 5/01
processor)
Syntax
CALL 55
POP [input image buffer status]
Example
>1 REM EXAMPLE PROGRAM
>120 CALL 55 : REM WAIT ON SLC
>130 POP S
>140 IF (S=2) THEN PRINT “THE SLC DOES NOT SUPPORT THIS
FUNCTION”
>150 IF (S=2) THEN STOP
>160 IF (S=0) THEN GOTO 120
>170 PRINT “INPUT IMAGE HAS BEEN READ”
READY
>RUN
INPUT IMAGE HAS BEEN READ
READY
>