Agilent Technologies FS2010 Podręcznik Użytkownika Pobierz pdf (Strona 43)

Programming with VISA 3

Agilent VISA User’s Guide 43

Sending I/O Commands

This section provides guidelines for sending I/O commands,

including:

• Types of I/O

• Using Formatted I/O

• Using Non- Formatted I/O

Types of I/O

Once you have established a communications session with a

device, you can start communicating with that device using

VISA's I/O routines. VISA provides both formatted and

non- formatted I/O routines.

•Formatted I/O converts mixed types of data under the

control of a format string. The data is buffered, thus

optimizing interface traffic.

• Non- formatted I/O sends or receives raw data to or from

a device. With non- formatted I/O, no format or conversion

of the data is performed. Thus, if formatted data is

required, it must be done by the user.

You can choose between VISA's formatted and non- formatted

I/O routines. However, you should not mix formatted I/O

and non- formatted I/O in the same session. See the

following sections for descriptions and code samples using

formatted I/O and non- formatted I/O in VISA.

Using Formatted I/O

The VISA formatted I/O mechanism is similar to the C stdio

mechanism. The VISA formatted I/O functions are viPrintf,

viQueryf, and viScanf. There are also two non- buffered and

non- formatted I/O functions that synchronously transfer

data, called viRead and viWrite, and two that

asynchronously transfer data, called viReadAsync and

viWriteAsync.

1 2 ... 38 39 40 41 42 43 44 45 46 47 48 ... 159 160

Brak uwag

Agilent Technologies FS2010 Podręcznik Użytkownika Strona 43