Dir

Type

Description

sesn

IN

ViSession

Resource Manager session (should always be the Default Resource Manager for VISA returned from viOpenDefaultRM).

rsrcName

IN

ViRsrc

Unique symbolic name (VISA address) of a resource. (See the following tables.) Can also be a VISA alias (defined in the Agilent Connection Expert utility).

accessMode

IN

ViAccessMode

Specifies the modes by which the resource is to be accessed. The value VI_EXCLUSIVE_LOCK is used to acquire an exclusive lock immediately upon opening a session. If a lock cannot be acquired, the session is closed and an error is returned.  The VI_LOAD_CONFIG value is used to configure attributes specified by some external configuration utility. If this value is not used, the session uses the default values provided by this specification. Multiple access modes can be used simultaneously by specifying a "bit-wise OR" of the values. (Must use VI_NULL in VISA 1.0.)

timeout

IN

ViUInt32

If the accessMode parameter requires a lock, this parameter specifies the absolute time period (in milliseconds) that the resource waits to get unlocked before this operation returns an error. Otherwise, this parameter is ignored. (Must use VI_NULL in VISA 1.0.)Note: The timeout parameter affects ONLY the LOCK, it does not impact the overall viOpen command timing.

vi

OUT

ViPSession

Unique logical identifier reference to a session.

Address String Grammar for rsrcName Parameter

Interface

Syntax

ASRL

ASRL[board][::INSTR]

GPIB

GPIB[board]::INTFC

GPIB-VXI

GPIB-VXI[board]::MEMACC

GPIB

GPIB[board]::primary address[::secondary address][::INSTR]

GPIB-VXI

GPIB-VXI[board]::VXI logical address[::INSTR]

GPIB-VXI

GPIB-VXI[board][::VXI logical address]::BACKPLANE

PXI

PXI[bus]::device[::function][::INSTR]

PXI

PXI[interface]::bus-device[.function][::INSTR]

PXI

PXI[interface]::CHASSISchassis::SLOTslot[::FUNCfunction][::INSTR]

PXI

PXI[interface]::MEMACC

TCPIP

TCPIP[board]::host address::port::SOCKET

TCPIP

TCPIP[board]::host address[::HiSLIP device name[,HiSLIP port]][::INSTR]

TCPIP

TCPIP[board]::host address[::LAN device name]::INSTR

USB

USB[board]::manufacturer ID::model code::serial number[::USB interface number][::INSTR]

VXI

VXI[board]::MEMACC

VXI

VXI[board]::VXI logical address[::INSTR]

VXI

VXI[board][::VXI logical address]::BACKPLANE

Examples of Address Strings for rsrcName Parameter

Address String

Description

ASRL1::INSTR

A serial device located on port 1.

GPIB::1::0::INSTR

A GPIB device at primary address 1 and secondary address 0 in GPIB interface 0.

GPIB2::INTFC

Interface or raw resource for GPIB interface 2.

GPIB-VXI::9::INSTR

A VXI device at logical address 9 in a GPIB-VXI controlled VXI system.

GPIB-VXI1::MEMACC

Board-level register access to GPIB-VXI interface number 1.

"MyDMM"

A device for which the VISA Alias myDMM has been created in the Agilent Connection Expert utility

PXI0::21::INSTR

PXI device 21 on bus 0

PXI0::3-18.2::INSTR

Function 2 on PXI device 18 on bus 3

PXI0::3-18::INSTR

PXI device 18 on bus 3.

PXI0::CHASSIS1::SLOT4::INSTR

PXI device in slot 4 of chassis 1.

PXI0::MEMACC

Access to system controller memory available to devices in the PXI system.

TCPIP0::[fe80::1]::hislip0::INSTR

A TCP/IP device using HiSLIP located at IPv6 IP address fe80::1.

TCPIP::devicename @company.com::INSTR

TCPIP device using VXI-11 located at the specified address. This uses the default LAN Device Name of inst0.

TCPIP0::1.2.3.4::999::SOCKET

Raw TCPIP access to port 999 at the specified address.

USB::0x1234::0x5678::A22-5::INSTR

A USB device with manufacturer ID 0x1234, model code 0x5678, and serial number A22-5. This uses the device’s first available USBTMC interface. This is usually number 0.

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.

Type ViStatus

This is the function return status. It returns either a completion code or an error code as follows.

Completion Codes

Description

VI_SUCCESS

Operation completed successfully.

VI_WARN_CONFIG_NLOADED

The specified configuration either does not exist or could not be loaded using VISA-specified defaults.

Error Codes

Description

VI_ERROR_ALLOC

Insufficient system resources to open a session.

VI_ERROR_INTF_NUM_NCONFIG

The interface type is valid but the specified interface number is not configured.

VI_ERROR_INV_ACC_MODE

Invalid access mode.

VI_ERROR_INV_RSRC_NAME

Invalid resource reference specified. Parsing error.

VI_ERROR_INV_SESSION
VI_ERROR_INV_OBJECT

The given session or object reference is invalid (both are the same value).

VI_ERROR_LIBRARY_NFOUND

A code library required by VISA could not be located or loaded.

VI_ERROR_NSUP_OPER

The given sesn does not support this function. For VISA, this function is supported only by the Default Resource Manager session.

VI_ERROR_RSRC_BUSY

The resource is valid but VISA cannot currently access it.

VI_ERROR_RSRC_LOCKED

Specified type of lock cannot be obtained because the resource is already locked with a lock type incompatible with the lock requested.

VI_ERROR_RSRC_NFOUND

Insufficient location information or resource not present in the system.

VI_ERROR_TMO

A session to the resource could not be obtained within the specified timeout period.