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4
Controlling Instruments Using the VISA Standard
The Serial Port Interface
The serial port interface is supported through a VISA-serial object. The
features associated with a VISA-serial object are similar to the features
associated with a serial port object. Therefore, only functions and properties
that are unique to VISA’s serial port interface are discussed in this section.
These unique features are associated with:
• Creating a VISA-serial object
• Configuring communication settings
Refer to Chapter 5, “Controlling Serial Port Instruments” to learn about
writing and reading text and binary data, using events and callbacks, using
serial port control lines, and so on.
Note The VISA-serial object does not support the serialbreak function, the
BreakInterruptFcn property, and the PinStatusFcn property.
Creating a VISA-Serial Object
You create a VISA-serial object with the visa function. Each VISA-serial object
is associated with an instrument connected to a serial port on your computer.
visa requires the vendor name and the resource name as input arguments. The
vendor name can be agilent, ni, or tek. The resource name consists of the
name of the serial port connected to your instrument. You can find the
VISA-serial resource name for a given instrument with the configuration tool
provided by your vendor, or with the instrhwinfo function. As described in
“Configuring Properties During Object Creation” on page 2-5, you can also
configure property values during object creation.
For example, to create a VISA-serial object that is associated with the COM1
port, and that uses National Instruments VISA
vs = visa('ni','ASRL1::INSTR');
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