Rockwell-automation 2708-NBD VBASIC Language Development Kit Uživatelský manuál stáhnout pdf (Strana 51)

A-B VBASIC and Visual BASIC

Appendix B

Differences Between

B–3

LINE INPUT Request$

IF Request$ = “JUMP” THEN CHAIN “JUMP”

The interpreter does not tolerate a CHAIN to a non–existent program. Make

sure that you have downloaded any program which will be CHAINed to,

before any other program attempts to CHAIN to it, or the program will crash

with a “Bad Chain File” error message. A special set of Network Directives

is required to download a program for the express purpose of a subsequent

CHAIN. See the User’s Guide for a further discussion of these Network

Directives.

CHR$(code)

Returns a one–character string whose ASCII code is the argument.

Msg$ = CHR$(34) + “Quoted string” + CHR$(34)

This example adds a double–quote character to the beginning and the end of

the string.

CINT(numeric–expression)

Converts a numeric–expression to an integer by rounding the expression’s

fractional part.

CLNG(numeric–expression)

Converts a numeric–expression to a long (4–byte) integer by rounding the

expression’s fractional part.

CLOSE [ [#]filenumber[,[#]filenumber]...]

Concludes I/O to a file or device. Closing some reserved files, such as

HOST, have additional side effects. See the description of those devices for

details.

OPEN “EMPLOYEE” FOR OUTPUT AS #1

PRINT #1, “Employee –”;EmpBadge$

CLOSE #1

CLS [{ 0 | 1 | 2 }]

Clears the front panel LCD, homes the cursor. All forms shown are

accepted, but all have the same effect.

CONST constname=expression

In a procedure a CONST overrides a GLOBAL variable of the same name.

The text of a string CONST is to be present in one place, regardless of the

number of times it is referenced. However, because string CONST

1 2 ... 46 47 48 49 50 51 52 53 54 55 56 ... 83 84

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Rockwell-automation 2708-NBD VBASIC Language Development Kit Uživatelský manuál Strana 51