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8303460000 Rev A IA672-04-01-Rev. I
7. PROGRAMMING USING VISA DRIVERS
7.1. VISA Description
In the test and measurement industry, Virtual Instrument Software Architecture (VISA) is a
popular framework that includes hardware drivers, configuration utilities and connection
managers. A variety of communication busses are supported. VISA drivers are available
from several instrument vendors.
Any programming language that supports Windows COM or DLL libraries can call the VISA
functions. VISA drivers may be downloaded for Windows, Linux and MAC OS. Some
licensing issues may apply.
Remote programming uses a computer’s LAN connection to send text commands to the
power supply, and to read text responses back. The format of the text messages is called
SCPI (see section 11).
7.2. VXI-11 Compatibility
VXI-11 is a protocol that allows communications between a computer port and an
instrument. VISA is built upon the VXI-11 specification. The Genesys™ power supply is
compatible with the VXI-11 protocols:
VXI–11 Device_link Open link to instrument
VXI–11 Device_write Write text to the instrument
VXI–11 Device_read Read text from an instrument
VXI–11 Destroy_link Close link to instrument
7.3. Opening the VISA Connection
Test and automation programs may easily be written if they use the VISA libraries. The
supported VISA functions include Open, Read, Write and Close.
A VISA resource descriptor is used to describe a particular supply. For a Genesys™ LAN
power supply, the descriptors are found on the supply’s Home web page. The VISA
resource may use the supply’s IP address or hostname.
Example VISA resource descriptors for the Genesys™ power supply with LAN are:
Format: TCPIP[board]::host address[::LAN device name][::INSTR]
[board] is the LAN card number, zero is optional
[::LAN device name] is by default “inst0”
[::INSTR] is optional
Examples: TCPIP::10.225.26.60::inst0::INSTR
TCPIP::169.254.57.10::INSTR
TCPIP1::GEN60-25-470::INSTR
See the sample programs, section 14, for examples
7.4. Communicating Using VISA
The VISA Write function will send SCPI commands to the power supply, the VISA read will
read the response returned from a SCPI query.
For programming examples and support, refer to the VISA vendor’s web site.
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