Rockwell-automation 1771-DB Basic Module User Manual - Series A Manual de usuario descargar pdf (Pagina 67)

Operating Functions

Chapter 5

5–30

Mode: RUN

Type: CONTROL

The ONERR[ln num] statement lets you handle arithmetic errors, if

they occur, during program execution. Only ARITH. OVERFLOW,

ARITH. UNDERFLOW, DIVIDE BY ZERO and BAD ARGUMENT

errors are “trapped” by the ONE RR statement. All other errors are

not “trapped”. If an arithmetic error occurs after the ONE RR

statement is executed, the module interpreter passes control to the line

number following the ONERR[ln num] statement. You handle the error

condition in a manner suitable to the particular application. The ONERR

command does not trap bad data entered during an input

instruction. This yields a “TRY AGAIN” message or “EXTRA

IGNORED” message. See Chapter 9 for an explanation of errors.

With the ONERR[ln num] statement, you have the option of

determining what type of error occurred. Do this by examining

external memory location 257 (101H) after the error condition is

trapped.

The error codes are:

ERROR CODE =10 – DIVIDE BY ZERO

ERROR CODE =20 – ARITH. OVERFLOW

ERROR CODE =30 – ARITH. UNDERFLOW

ERROR CODE =40 – BAD ARGUMENT

You can examine this location by using an XBY(257) statement.

Example:

PRINT XBY(257)

E XBY(257)

5.4.19

Statement: ONERR

[ln num)

1 2 ... 62 63 64 65 66 67 68 69 70 71 72 ... 166 167

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Rockwell-automation 1771-DB Basic Module User Manual - Series A Manual de usuario Pagina 67