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NI-VISA Documentation
Width of access
NI-VISA
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The width (in bits) of the register operation.
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Table of contents
NI-VISA Help
Related Documentation
Using Help
Conventions
Navigating Help
Searching Help
Printing Help File Topics
Introduction
What You Need to Get Started
VXIplug&play Overview
Supported Platforms
User Reference
How to Use the User Reference Topics
Introductory Programming Examples
Example of Message-Based Communication
C Example
Visual Basic Example
Example Discussion
Example of Register-Based Communication
C Example
Visual Basic Example
Example Discussion
Example of Handling Events
Callbacks
Queuing
C Example
Visual Basic Example
Example Discussion
Example of Locking
C Example
Visual Basic Example
Example Discussion
VISA Overview
Background
VISA Terminology
Beginning Terminology
Communication Channels: Sessions
The Resource Manager
Examples of Interface Independence
Initializing Your VISA Application
Introduction
Opening a Session
C Example
Visual Basic Example
Finding Resources
C Example
Visual Basic Example
Finding VISA Resources Using Regular Expressions
Attribute-Based Resource Matching
C Example
Visual Basic Example
Configuring a Session
Accessing Attributes
Common Considerations for Using Attributes
Message-Based Communication
Introduction
Basic I/O Services
Synchronous Read/Write Services
Asynchronous Read/Write Services
Clear Service
Trigger Service
Status/Service Request Service
Example VISA Message-Based Application
C Example
Visual Basic Example
Formatted I/O Services
Formatted I/O Operations
I/O Buffer Operations
Variable List Operations
Manually Flushing the Formatted I/O Buffers
Automatically Flushing the Formatted I/O Buffers
Resizing the Formatted I/O Buffers
Formatted I/O Read and Low-Level I/O Receive Buffers
Formatted I/O Write and Low-Level I/O Transmit Buffers
Recommendations for Using the VISA Buffers
Formatted I/O Instrument Driver Examples
Integers
Floating Point Values
Strings
Data Blocks
Register-Based Communication
Introduction
High-Level Access Operations
High-Level Block Operations
Low-Level Access Operations
Overview of Register Accesses from Computers
Using VISA to Perform Low-Level Register Access
Operations vs. Pointer Dereference
Manipulating the Pointer
C Example
Visual Basic Example
Bus Errors
Comparison of High-Level and Low-Level Access
Speed
Ease of Use
Accessing Multiple Address Spaces
Shared Memory Operations
Shared Memory Sample Code
C Example
Visual Basic Example
VISA Events
Introduction
Supported Events
Enabling and Disabling Events
Queuing
Callbacks
Callback Modes
Independent Queues
The userHandle Parameter
Queuing and Callback Mechanism Sample Code
C Example
Visual Basic Example
Life of the Event Context
Event Context with the Queuing Mechanism
Event Context with the Callback Mechanism
Exception Handling
VISA Locks
Introduction
Lock Types
Lock Sharing
Acquiring an Exclusive Lock While Owning a Shared Lock
Nested Locks
Locking Sample Code
C Example
Visual Basic Example
.NET
NI-VISA Utilities
NI Spy: Debugging Tool
Interactive Control of VISA
Measurement & Automation Explorer (MAX)
visaconf
NI-VISA Driver Wizard
Overview
Hardware Bus
Basic FireWire Device Information
Basic PXI/PCI Device Information
Basic USB Device Information
Interrupt Detection Information
Interrupt Removal Information
NI-VISA PXI Interrupt Information
Disarm Interrupt Information
PXI Express Configuration
Output Files Information
Installation Options
Example for PXI
Example for USB
Interface-Specific Information
GPIB
Introduction to Programming GPIB Devices in VISA
Comparison Between NI-VISA and NI-488.2 APIs
Board-Level Programming
GPIB Summary
GPIB-VXI
Introduction to Programming GPIB-VXI Devices in VISA
Register-Based Programming with the GPIB-VXI
Additional Programming Issues
GPIB-VXI Summary
VXI
Introduction to Programming VXI Devices in VISA
VXI/VME Interrupts and Asynchronous Events in VISA
Performing Arbitrary Access to VXI Memory with VISA
Other VXI Resource Classes and VISA
Comparison Between NI-VISA and NI-VXI APIs
Summary of VXI in VISA
PXI/PCI
Introduction to Programming PXI Devices in NI-VISA
User-Level Functionality
Configuring NI-VISA to Recognize a PXI Device
Using LabWindows/CVI to Install Your Device .inf Files
Other PXI Resource Classes and VISA
PXI Summary
Using the NI-VISA Driver Wizard and NI-VISA to Register-Level Program a PXI/PCI Device Under Windows
PXI and VISA Background
Configuring NI-VISA to Recognize a PXI/PCI Device
Hardware Bus
Basic Device Information
Interrupt Detection Information
Interrupt Removal Information
Interrupt Disarm Information
PXI Express Configuration Information
Output Files Generation
Installation Options
Using NI-VISA to Communicate with a PXI/PCI Device
Step 1 -- Initialize the Device
Step 2 -- Communicating with the PXI Device
Step 3 -- Closing the Device
Using NI-VISA to Handle Events from a PXI/PCI Device
Serial
Introduction to Programming Serial Devices in VISA
Default vs. Configured Communication Settings
Controlling the Serial I/O Buffers
National Instruments ENET Serial Controllers
Serial Summary
Ethernet
Introduction to Programming Ethernet Devices in VISA
VISA Sockets vs. Other Sockets APIs
Ethernet Summary
Remote NI-VISA
Introduction to Programming Remote Devices in NI-VISA
How to Configure and Use Remote NI-VISA
Remote NI-VISA Summary
USB
Introduction to Programming USB Devices in VISA
Configuring NI-VISA to Recognize a RAW USB Device
USB Summary
USB Instrument Control Tutorial
USB and VISA Background
Configuring NI-VISA to Control Your USB Device
Create the .inf File Using the NI-VISA Driver Wizard
Install the .inf Files and USB Device
Test the Device with VISA Interactive Control
Using NI-VISA to Communicate with Your USB Device
USB on Linux and Mac
FireWire
Introduction to Programming FireWire Devices in VISA
Configuring NI-VISA to Recognize an INSTR FireWire Device
FireWire Summary
Function Reference
Overview of the VISA API
Description of the API
VISA Access Mechanisms
VISA Resource Types
VISA Resource Syntax and Examples
Attributes
Attributes
VI_ATTR_4882_COMPLIANT
VI_ATTR_ASRL_ALLOW_TRANSMIT
VI_ATTR_ASRL_AVAIL_NUM
VI_ATTR_ASRL_BAUD
VI_ATTR_ASRL_BREAK_LEN
VI_ATTR_ASRL_BREAK_STATE
VI_ATTR_ASRL_CONNECTED
VI_ATTR_ASRL_CTS_STATE
VI_ATTR_ASRL_DATA_BITS
VI_ATTR_ASRL_DCD_STATE
VI_ATTR_ASRL_DISCARD_NULL
VI_ATTR_ASRL_DSR_STATE
VI_ATTR_ASRL_DTR_STATE
VI_ATTR_ASRL_END_IN
VI_ATTR_ASRL_END_OUT
VI_ATTR_ASRL_FLOW_CNTRL
VI_ATTR_ASRL_PARITY
VI_ATTR_ASRL_REPLACE_CHAR
VI_ATTR_ASRL_RI_STATE
VI_ATTR_ASRL_RTS_STATE
VI_ATTR_ASRL_STOP_BITS
VI_ATTR_ASRL_WIRE_MODE
VI_ATTR_ASRL_XOFF_CHAR
VI_ATTR_ASRL_XON_CHAR
VI_ATTR_BUFFER
VI_ATTR_CMDR_LA
VI_ATTR_DEST_ACCESS_PRIV
VI_ATTR_DEST_BYTE_ORDER
VI_ATTR_DEST_INCREMENT
VI_ATTR_DEV_STATUS_BYTE
VI_ATTR_DMA_ALLOW_EN
VI_ATTR_EVENT_TYPE
VI_ATTR_FDC_CHNL
VI_ATTR_FDC_MODE
VI_ATTR_FDC_USE_PAIR
VI_ATTR_FILE_APPEND_EN
VI_ATTR_FIREWIRE_DEST_UPPER_OFFSET
VI_ATTR_FIREWIRE_LOWER_32_CHIP_ID
VI_ATTR_FIREWIRE_SRC_UPPER_OFFSET
VI_ATTR_FIREWIRE_UPPER_8_CHIP_ID
VI_ATTR_FIREWIRE_VENDOR_ID
VI_ATTR_FIREWIRE_WIN_UPPER_OFFSET
VI_ATTR_GPIB_ADDR_STATE
VI_ATTR_GPIB_ATN_STATE
VI_ATTR_GPIB_CIC_STATE
VI_ATTR_GPIB_HS488_CBL_LEN
VI_ATTR_GPIB_NDAC_STATE
VI_ATTR_GPIB_PRIMARY_ADDR
VI_ATTR_GPIB_READDR_EN
VI_ATTR_GPIB_RECV_CIC_STATE
VI_ATTR_GPIB_REN_STATE
VI_ATTR_GPIB_SECONDARY_ADDR
VI_ATTR_GPIB_SRQ_STATE
VI_ATTR_GPIB_SYS_CNTRL_STATE
VI_ATTR_GPIB_UNADDR_EN
VI_ATTR_IMMEDIATE_SERV
VI_ATTR_INTF_INST_NAME
VI_ATTR_INTF_NUM
VI_ATTR_INTF_PARENT_NUM
VI_ATTR_INTF_TYPE
VI_ATTR_INTR_STATUS_ID
VI_ATTR_IO_PROT
VI_ATTR_JOB_ID
VI_ATTR_MAINFRAME_LA
VI_ATTR_MANF_ID
VI_ATTR_MANF_NAME
VI_ATTR_MAX_QUEUE_LENGTH
VI_ATTR_MEM_BASE/VI_ATTR_MEM_BASE_32/VI_ATTR_MEM_BASE_64
VI_ATTR_MEM_SIZE/VI_ATTR_MEM_SIZE_32/VI_ATTR_MEM_SIZE_64
VI_ATTR_MEM_SPACE
VI_ATTR_MODEL_CODE
VI_ATTR_MODEL_NAME
VI_ATTR_OPER_NAME
VI_ATTR_PXI_ACTUAL_LWIDTH
VI_ATTR_PXI_BUS_NUM
VI_ATTR_PXI_CHASSIS
VI_ATTR_PXI_DEST_TRIG_BUS
VI_ATTR_PXI_DEV_NUM
VI_ATTR_PXI_DSTAR_BUS
VI_ATTR_PXI_DSTAR_SET
VI_ATTR_PXI_FUNC_NUM
VI_ATTR_PXI_IS_EXPRESS
VI_ATTR_PXI_MAX_LWIDTH
VI_ATTR_PXI_MEM_BASE_BAR0/1/2/3/4/5
VI_ATTR_PXI_MEM_SIZE_BAR0/1/2/3/4/5
VI_ATTR_PXI_MEM_TYPE_BAR0/1/2/3/4/5
VI_ATTR_PXI_RECV_INTR_DATA
VI_ATTR_PXI_RECV_INTR_SEQ
VI_ATTR_PXI_SLOT_LBUS_LEFT
VI_ATTR_PXI_SLOT_LBUS_RIGHT
VI_ATTR_PXI_SLOT_LWIDTH
VI_ATTR_PXI_SLOTPATH
VI_ATTR_PXI_SRC_TRIG_BUS
VI_ATTR_PXI_STAR_TRIG_BUS
VI_ATTR_PXI_STAR_TRIG_LINE
VI_ATTR_PXI_TRIG_BUS
VI_ATTR_RD_BUF_OPER_MODE
VI_ATTR_RD_BUF_SIZE
VI_ATTR_RECV_INTR_LEVEL
VI_ATTR_RECV_TRIG_ID
VI_ATTR_RET_COUNT/VI_ATTR_RET_COUNT_32/VI_ATTR_RET_COUNT_64
VI_ATTR_RM_SESSION
VI_ATTR_RSRC_CLASS
VI_ATTR_RSRC_IMPL_VERSION
VI_ATTR_RSRC_LOCK_STATE
VI_ATTR_RSRC_MANF_ID
VI_ATTR_RSRC_MANF_NAME
VI_ATTR_RSRC_NAME
VI_ATTR_RSRC_SPEC_VERSION
VI_ATTR_SEND_END_EN
VI_ATTR_SIGP_STATUS_ID
VI_ATTR_SLOT
VI_ATTR_SRC_ACCESS_PRIV
VI_ATTR_SRC_BYTE_ORDER
VI_ATTR_SRC_INCREMENT
VI_ATTR_STATUS
VI_ATTR_SUPPRESS_END_EN
VI_ATTR_TCPIP_ADDR
VI_ATTR_TCPIP_DEVICE_NAME
VI_ATTR_TCPIP_HOSTNAME
VI_ATTR_TCPIP_KEEPALIVE
VI_ATTR_TCPIP_NODELAY
VI_ATTR_TCPIP_PORT
VI_ATTR_TERMCHAR
VI_ATTR_TERMCHAR_EN
VI_ATTR_TMO_VALUE
VI_ATTR_TRIG_ID
VI_ATTR_USB_ALT_SETTING
VI_ATTR_USB_BULK_IN_PIPE
VI_ATTR_USB_BULK_IN_STATUS
VI_ATTR_USB_BULK_OUT_PIPE
VI_ATTR_USB_BULK_OUT_STATUS
VI_ATTR_USB_CLASS
VI_ATTR_USB_CTRL_PIPE
VI_ATTR_USB_END_IN
VI_ATTR_USB_INTFC_NUM
VI_ATTR_USB_INTR_IN_PIPE
VI_ATTR_USB_INTR_IN_STATUS
VI_ATTR_USB_MAX_INTR_SIZE
VI_ATTR_USB_NUM_INTFCS
VI_ATTR_USB_NUM_PIPES
VI_ATTR_USB_PROTOCOL
VI_ATTR_USB_RECV_INTR_DATA
VI_ATTR_USB_RECV_INTR_SIZE
VI_ATTR_USB_SERIAL_NUM
VI_ATTR_USB_SUBCLASS
VI_ATTR_USER_DATA/VI_ATTR_USER_DATA_32/VI_ATTR_USER_DATA_64
VI_ATTR_VXI_DEV_CLASS
VI_ATTR_VXI_LA
VI_ATTR_VXI_TRIG_STATUS
VI_ATTR_VXI_TRIG_SUPPORT
VI_ATTR_VXI_VME_INTR_STATUS
VI_ATTR_VXI_VME_SYSFAIL_STATE
VI_ATTR_WIN_ACCESS
VI_ATTR_WIN_ACCESS_PRIV
VI_ATTR_WIN_BASE_ADDR/VI_ATTR_WIN_BASE_ADDR_32/VI_ATTR_WIN_BASE_ADDR_64
VI_ATTR_WIN_BYTE_ORDER
VI_ATTR_WIN_SIZE/VI_ATTR_WIN_SIZE_32/VI_ATTR_WIN_SIZE_64
VI_ATTR_WR_BUF_OPER_MODE
VI_ATTR_WR_BUF_SIZE
Events
Events
VI_EVENT_ASRL_BREAK
VI_EVENT_ASRL_CHAR
VI_EVENT_ASRL_CTS
VI_EVENT_ASRL_DCD
VI_EVENT_ASRL_DSR
VI_EVENT_ASRL_RI
VI_EVENT_ASRL_TERMCHAR
VI_EVENT_CLEAR
VI_EVENT_EXCEPTION
VI_EVENT_GPIB_CIC
VI_EVENT_GPIB_LISTEN
VI_EVENT_GPIB_TALK
VI_EVENT_IO_COMPLETION
VI_EVENT_PXI_INTR
VI_EVENT_SERVICE_REQ
VI_EVENT_TRIG
VI_EVENT_USB_INTR
VI_EVENT_VXI_SIGP
VI_EVENT_VXI_VME_INTR
VI_EVENT_VXI_VME_SYSFAIL
VI_EVENT_VXI_VME_SYSRESET
Operations
Operations
viAssertIntrSignal
viAssertTrigger
viAssertUtilSignal
viBufRead
viBufWrite
viClear
viClose
viDisableEvent
viDiscardEvents
viEnableEvent
viEventHandler
viFindNext
viFindRsrc
viFlush
viGetAttribute
viGpibCommand
viGpibControlATN
viGpibControlREN
viGpibPassControl
viGpibSendIFC
viIn8/viIn16/viIn32/viIn64
viIn8Ex/viIn16Ex/viIn32Ex/viIn64Ex
viInstallHandler
viLock
viMapAddress/viMapAddressEx
viMapTrigger
viMemAlloc/viMemAllocEx
viMemFree/viMemFreeEx
viMove/viMoveEx
viMoveAsync/viMoveAsyncEx
viMoveIn8/viMoveIn16/viMoveIn32/viMoveIn64
viMoveIn8Ex/viMoveIn16Ex/viMoveIn32Ex/viMoveIn64Ex
viMoveOut8/viMoveOut16/viMoveOut32/viMoveOut64
viMoveOut8Ex/viMoveOut16Ex/viMoveOut32Ex/viMoveOut64Ex
viOpen
viOpenDefaultRM
viOut8/viOut16/viOut32/viOut64
viOut8Ex/viOut16Ex/viOut32Ex/viOut64Ex
viParseRsrc
viParseRsrcEx
viPeek8/viPeek16/viPeek32/viPeek64
viPoke8/viPoke16/viPoke32/viPoke64
viPrintf
viQueryf
viRead
viReadAsync
viReadSTB
viReadToFile
viScanf
viSetAttribute
viSetBuf
viSPrintf
viSScanf
viStatusDesc
viTerminate
viUninstallHandler
viUnlock
viUnmapAddress
viUnmapTrigger
viUsbControlIn
viUsbControlOut
viVPrintf
viVQueryf
viVScanf
viVSPrintf
viVSScanf
viVxiCommandQuery
viWaitOnEvent
viWrite
viWriteAsync
viWriteFromFile
Resources
Resources
VISA Resource Template
VISA Resource Manager
INSTR Resource
MEMACC Resource
INTFC Resource
BACKPLANE Resource
SERVANT Resource
SOCKET Resource
RAW Resource
Status Codes
Completion Codes
Error Codes
Platform-Specific and Portability Issues
Programming Considerations
Multiple Applications Using the NI-VISA Driver
Low-Level Access Functions
Interrupt Callback Handlers
Multiple Interface Support Issues
VXI and GPIB Platforms
Serial Port Support
C Example
Visual Basic Example
VME Support
Glossary
Important Information
Warranty
Copyright
Trademarks
Patents
Warning Regarding Use of NI Products
Technical Support and Professional Services
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