TDK-Lambda HFE1600 SERIES, Руководство пользователя

Страница: 30 / 40

6. PROGRAMMING USING VISA DRIVERS
6.1 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.
6.2 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 HFE LAN module is compatible
with the VXI-11 protocols.
o
VXI–11 Device_link Open link to instrument
o VXI–11 Device_write Write text to the instrument
o VXI–11 Device_read Read text from an instrument
o VXI–11 Destroy_link Close link to instrument
6.3 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 module. For HFE LAN module,
the descriptors are found on the module’s Home web page. The VISA resource may use
the module’s IP address or hostname.
Example VISA resource descriptors for the HFE LAN module are:
Format: TCPIP[board]::IP address/Host Name[::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
TCPIP1::HFE-LAN-222::INSTR
6.4 Communicating Using VISA
The VISA Write function will send commands to the module, the VISA read will read the
response returned from a query.
30