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.. _resource_names:
VISA resource names
===================
If you use the function :func:`open_resource`, you must tell this
function the *VISA resource name* of the instrument you want to
connect to. Generally, it starts with the bus type, followed by a
double colon ``"::"``, followed by the number within the bus. For
example,
.. code-block:: none
GPIB::10
denotes the GPIB instrument with the number 10. If you have two GPIB
boards and the instrument is connected to board number 1, you must
write
.. code-block:: none
GPIB1::10
As for the bus, things like ``"GPIB"``, ``"USB"``, ``"ASRL"`` (for
serial/parallel interface) are possible. So for connecting to an
instrument at COM2, the resource name is
.. code-block:: none
ASRL2
(Since only one instrument can be connected with one serial interface,
there is no double colon parameter.) However, most VISA systems allow
aliases such as ``"COM2"`` or ``"LPT1"``. You may also add your own
aliases.
The resource name is case-insensitive. It doesn't matter whether you
say ``"ASRL2"`` or ``"asrl2"``. For further information, I have to refer
you to a comprehensive VISA description like
`<http://www.ni.com/pdf/manuals/370423a.pdf>`_.
VISA Resource Syntax and Examples
---------------------------------
(This is adapted from the VISA manual)
The following table shows the grammar for the address string. Optional string segments are shown in square brackets ([ ]).
================= ========================================================================================
Interface Syntax
================= ========================================================================================
ENET-Serial INSTR ASRL[0]::host address::serial port::INSTR
----------------- ----------------------------------------------------------------------------------------
GPIB INSTR GPIB[board]::primary address[::secondary address][::INSTR]
GPIB INTFC GPIB[board]::INTFC
----------------- ----------------------------------------------------------------------------------------
PXI BACKPLANE PXI[interface]::chassis number::BACKPLANE
PXI INSTR PXI[bus]::device[::function][::INSTR]
PXI INSTR PXI[interface]::bus-device[.function][::INSTR]
PXI INSTR PXI[interface]::CHASSISchassis number::SLOTslot number[::FUNCfunction][::INSTR]
PXI MEMACC PXI[interface]::MEMACC
----------------- ----------------------------------------------------------------------------------------
Remote NI-VISA visa://host address[:server port]/remote resource
----------------- ----------------------------------------------------------------------------------------
Serial INSTR ASRLboard[::INSTR]
----------------- ----------------------------------------------------------------------------------------
TCPIP INSTR TCPIP[board]::host address[::LAN device name][::INSTR]
TCPIP SOCKET TCPIP[board]::host address::port::SOCKET
----------------- ----------------------------------------------------------------------------------------
USB INSTR USB[board]::manufacturer ID::model code::serial number[::USB interface number][::INSTR]
USB RAW USB[board]::manufacturer ID::model code::serial number[::USB interface number]::RAW
----------------- ----------------------------------------------------------------------------------------
VXI BACKPLANE VXI[board][::VXI logical address]::BACKPLANE
VXI INSTR VXI[board]::VXI logical address[::INSTR]
VXI MEMACC VXI[board]::MEMACC
VXI SERVANT VXI[board]::SERVANT
================= ========================================================================================
Use the GPIB keyword to establish communication with GPIB resources. Use the VXI keyword for VXI resources via embedded, MXIbus, or 1394 controllers. Use the ASRL keyword to establish communication with an asynchronous serial (such as RS-232 or RS-485) device. Use the PXI keyword for PXI and PCI resources. Use the TCPIP keyword for Ethernet communication.
The following table shows the default value for optional string segments.
======================== ==================================
Optional String Segments Default Value
======================== ==================================
board 0
GPIB secondary address none
LAN device name inst0
PXI bus 0
PXI function 0
USB interface number lowest numbered relevant interface
======================== ==================================
The following table shows examples of address strings:
================================ =============================================
Address String Description
================================ =============================================
ASRL::1.2.3.4::2::INSTR A serial device attached to port 2 of the
ENET Serial controller at address 1.2.3.4.
-------------------------------- ---------------------------------------------
ASRL1::INSTR A serial device attached to interface ASRL1.
-------------------------------- ---------------------------------------------
GPIB::1::0::INSTR A GPIB device at primary address 1 and
secondary address 0 in GPIB interface 0.
-------------------------------- ---------------------------------------------
GPIB2::INTFC Interface or raw board resource for GPIB
interface 2.
-------------------------------- ---------------------------------------------
PXI::15::INSTR PXI device number 15 on bus 0 with implied
function 0.
-------------------------------- ---------------------------------------------
PXI::2::BACKPLANE Backplane resource for chassis 2 on the
default PXI system, which is interface 0.
-------------------------------- ---------------------------------------------
PXI::CHASSIS1::SLOT3 PXI device in slot number 3 of the PXI chassis
configured as chassis 1.
-------------------------------- ---------------------------------------------
PXI0::2-12.1::INSTR PXI bus number 2, device 12 with function 1.
-------------------------------- ---------------------------------------------
PXI0::MEMACC PXI MEMACC session.
-------------------------------- ---------------------------------------------
TCPIP::dev.company.com::INSTR A TCP/IP device using VXI-11 or LXI located at
the specified address. This uses the default
LAN Device Name of inst0.
-------------------------------- ---------------------------------------------
TCPIP0::1.2.3.4::999::SOCKET Raw TCP/IP access to port 999 at the specified
IP address.
-------------------------------- ---------------------------------------------
USB::0x1234::125::A22-5::INSTR A USB Test & Measurement class device with
manufacturer ID 0x1234, model code 125, and
serial number A22-5. This uses the device's
first available USBTMC interface. This is
usually number 0.
-------------------------------- ---------------------------------------------
USB::0x5678::0x33::SN999::1::RAW A raw USB nonclass device with manufacturer
ID 0x5678, model code 0x33, and serial number
SN999. This uses the device's interface number 1.
-------------------------------- ---------------------------------------------
visa://hostname/ASRL1::INSTR The resource ASRL1::INSTR on the specified
remote system.
-------------------------------- ---------------------------------------------
VXI::1::BACKPLANE Mainframe resource for chassis 1 on the default
VXI system, which is interface 0.
-------------------------------- ---------------------------------------------
VXI::MEMACC Board-level register access to the VXI interface.
-------------------------------- ---------------------------------------------
VXI0::1::INSTR A VXI device at logical address 1 in VXI
interface VXI0.
-------------------------------- ---------------------------------------------
VXI0::SERVANT Servant/device-side resource for VXI interface 0.
================================ =============================================
|
