Rockwell-automation 2708-NBD VBASIC Language Development Kit Instrukcja Użytkownika Pobierz pdf (Strona 50)

A-B VBASIC and Visual BASIC

Appendix B

Differences Between

B–2

b. # suffix on variables

c. Floating–point constants with 8 or more significant digits

d. AS DOUBLE clauses

e. Functions involving DOUBLE, such as CVD and MKD

9. Restriction on the exponentiation operator

Exponentiation is implemented by repetitive multiplication, so small

exponents are recommended. Full real exponentiation is provided in the

function called “Power!” in the BASIC source file MATH.BAS. A-B

VBASIC supports exponentiation to positive integer powers only. For

example:

SUPPORTED: X^2

NOT SUPPORTED : X^5.7 or X^–2

10.Unsupported math intrinsics

These intrinsic functions, relating to exponent and trigonometric functions

are not implemented in the interpreter running in the DH5 terminal, but

BASIC source code implementing all of the below is provided in the file

MATH.BAS and may be copied into programs as required:

ATN COS EXP LOG SIN SQR TAN

ABS(numeric–expression)

Returns the absolute value of a numeric expression. ABS(–1) and ABS(1)

are both 1.

ASC(string–expression)

Returns the ASCII value of the first character in string–expression

BEEP

Sounds the speaker. Produces the same sound as PRINT CHR$(7).

CDBL(numeric–expression)

No longer supported. Converts a numeric–expression to a double–precision

number. Note the restrictions on DOUBLE precision usage above.

CHAIN filespec

Transfers control from current program to another program residing in file

memory. COMMON is NOT supported. Therefore, all variables are lost

between the CHAIN unless first stored in a file and retrieved after the

CHAINing.

Supported A-B VBASIC

Keywords

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Rockwell-automation 2708-NBD VBASIC Language Development Kit Instrukcja Użytkownika Strona 50