Rockwell Automation 1771-DB BASIC MODULE User Manual

Page 351

Troubleshooting

Appendix C

C –3

Occurs when:

This error
message:

BAD ARGUMENT

the argument of an operator is not within the limits of the operator

for example:

SQR(-12) generates a BAD ARGUMENT error because the value of the SQR
argument is limited to positive numbers

BAD SYNTAX

an invalid BASIC module command, statement or operator is entered and BASIC
cannot process the entry

C-STACK

•

the C-stack (control stack) pointer is forced “out of bounds”

•

you attempt to use more control stack than is available in the module

•

you execute a RETURN before a GOSUB, a WHILE or UNTIL before a DO, or
a NEXT before a FOR (See Chapter 11 for a description of these statements.)

•

you jump out of loop structures such as DO WHILE

CAN’T CONTINUE

•

you edit the program after halting execution and then enter the CONT
command

•

you enter

while in a call routine

you can halt program execution by either entering

or by

executing a STOP statement. Normally, program execution continues after

entering the CONT command. You must enter

during program

execution or you must execute a STOP statement before the CONT command
can work.

Ctrl

DIVIDE BY ZERO

you attempt to divide by zero

EXTRA IGNORED

an INPUT statement (page 11 -17) requiring numeric data, receives numeric data
followed by letters. Letters are ignored. Error also occurs from CALL 61 (page
12 -60).

MEMORY
ALLOCATION

•

user memory (RAM) is full

•

BASIC cannot determine memory bounds because the system control value
MTOP is altered

•

RAM contains an incomplete program file

•

you attempt to access STRINGS that are “outside” the defined string limits

NO DATA

a READ statement is executed and no DATA statement exists or all DATA was
read and a RESTORE instruction was not executed. (See Chapter 11 for a
description of these statements.)

the message ERROR: NO DATA - IN LINE XXX is printed to the console device.

PROGRAMMING

the BASIC module is programming an EEPROM. An error during programming
destroys the EPROM file structure. You cannot save any more programs on that
particular EEPROM once a PROGRAMMING error occurs. If the EEPROM size is
exceeded, the previously stored program may be partially altered.

Application errors such as divide by zero error, syntax error, receipt of a

Ctrl

(page 10 -4), and execution of STOP (page 11 -36) or END

(page 11 -10) statements cause the BASIC module to return to the
Command mode from Run mode. Use CALL 38 (EXPANDED ONERR)
(page 12 -36) to jump to an interrupt routine instead of returning to the
Command mode.