Rockwell Automation 1746-BAS BASIC LANGUAGE - Manual (Page 103)

Publication 1746-RM001A-US-P
Execution Control and Interrupt Support Functions 8-7
Syntax
PUSH [0 or 1]
CALL 38
Example
>1 REM EXAMPLE PROGRAM
>10 REM ENABLE EXPANDED ONERR FUNCTION
>20 ONERR 160
>30 PUSH 1
>40 CALL 38
>50 CALL 53: REM GET DATA FROM OUTPUT IMAGE
>60 PUSH 201: REM ADDRESS OF SECOND WORD IN BUFFER
>70 CALL 14: REM GET DATA FROM INPUT BUFFER
>80 POP X: REM VALUE FROM INPUT BUFFER
>90 A=(X*2.499733)-8191.625
>100 PUSH A: REM RESULT OF ABOVE CALCULATION
>110 PUSH 201: REM WORD NUMBER OF BASIC OUTPUT BUFFER
>120 CALL 24: REM BASIC FLOATING POINT TO 16-BIT SIGNED
INTEGER
>130 CALL 54: REM OUTPUT BUFFER TO SLC INPUT FILE
>140 POP Y: REM SLC PROCESSOR STATUS
>150 IF (Y<>0) THEN PRINT “PROCESSOR NOT IN RUN MODE”
>160 GOTO 50
>170 PRINT “ERROR CODE WAS”,XBY(257) : REM BEGINNING OF ONERR
ROUTINE
>175 PRINT “AT LINE “, (256*XBY (69FDH) + XBY(69FEH))
>180 GOTO 50
>190 END
The error in the example above is a missing POP for CALL 53. The missing POP
will cause an A-Stack error and would normally put the processor in Command
mode. When this occurs, print the error code and resume running the program.