Rockwell Automation 1771-DB Basic Module User Manual - Series A - Manual (Page 153)

Chapter 9
Error Messages and Anomalies
After reading this chapter you should be familiar with the module’s error
messages and anomalies.
When BASIC is in the RUN mode the format of the ERROR messages is
as follows:
ERROR: XXX – IN LINE YYY
YYY BASIC STATEMENT
X
Where XXX is the ERROR TYPE and YYY is the line number of the
program in which the error occurred. A specific example is:
ERROR: BAD SYNTAX – IN LINE 10
10 PRINT 34*21*
X
The X shows approximately where the ERROR occurred in the line
number. The specific location of the X may be off by one or two characters
or expressions depending on the type of error and where the error occurred
in the program. If an ERROR occurs in the COMMAND MODE only the
ERROR TYPE is printed out, not the line number. The ERROR TYPES
are as follows:
A-STACK — An A-STACK (ARGUMENT STACK) error occurs when
the argument stack pointer is forced “out of bounds”. An “out of bounds”
condition occurs if:
you overflow the argument stack by PUSHing too many expressions
onto the stack.
you attempt to POP data off the stack when no data is present.
ARITH. OVERFLOW — An ARITH. OVERFLOW occurs when an
arithmetic operation exceeds the upper limit of a module floating point
number. The largest floating point number in the BASIC Module is
+/–.99999999E+127. For example, 1E+70*1E+70 causes an ARITH.
OVERFLOW error.
9.1
Chapter Objectives
9.2
Error Messages from
BASIC