IVI Driver Help

Edition Date: August 2011

Part Number: 370430H-01

»View Product Info
Download Help (Windows Only)

Symbol Prefix Value
p pico 10 -12
n nano 10 -9
µ micro 10 -6
m milli 10 -3
k kilo 10 3
M mega 10 6
G giga 10 9
T tera 10 12


1D One-dimensional.
2D Two-dimensional.
Delta; difference.
x denotes the value by which x changes from one index to the next.


A Amperes.
A/D Analog-to-digital; analog/digital.
absolute coordinates Picture coordinates relative to the origin (0,0) of the picture indicator.
absolute path File or directory path that describes the location relative to the top level of the file system.
AC Alternating current.
active window Window that is currently set to accept user input, usually the frontmost window. The titlebar of an active window is highlighted. Make a window active by clicking it or by selecting it from the Windows menu.
ADEApplication Development Environment. An environment that provides users various software development tools for the development of automated test systems. Examples of ADEs include National Instruments LabVIEW and National Instruments LabWindows/CVI.
AI Analog input.
analog trigger Trigger that occurs at a user-selected level and slope on an incoming analog signal. You can set triggering to occur at a specified voltage on either an increasing or a decreasing signal (positive or negative slope).
ANSI American National Standards Institute.
APIApplication Programming Interface.
Application Programming Interface (API) A standardized set of subroutines or functions along with the parameters that a program can call.
array Ordered, indexed list of data elements of the same type.
ASCII American Standard Code for Information Interchange.


base class capabilitiesThe minimum set of functions, attributes, and attribute values that an IVI driver must implement to claim compliance with an instrument class specification. For example, the base class capabilities of the oscilloscope class have functions and attributes that configure an edge-triggered acquisition, initiate an acquisition, and return the acquired waveform. An IVI class-compliant specific driver implements all the base capabilities for a particular class.
behavior modelA diagram indicating an instrument's possible states, the functions that cause it to transition between states, and the attributes that affect tis behavior in each state.


capability groupA set of functions, attributes, and attribute values defined in an IVI Foundation specification. There are four different types of instrument capabilities—Inherent Capabilities, Base Class Capabilities, Class Extension Capabilities, and instrument specific driver Capabilities.
channel stringAn instrument specific driver string that refers to a particular channel of a device. An IVI specific driver that implements channels defines the channel strings that it recognizes. A channel string is an example of a repeated capability identifier.
channelOne of multiple physical inputs or outputs to an instrument. A set of channels is a type of repeated capability.
class driverAn instrument driver that provides a generic programming interface to instruments of a particular class. From your test program, you make calls to a class driver, which in turn communicates through a specific driver for your instrument. You can change the specific instrument driver (and corresponding instrument) in your system underneath the class driver without affecting your test code.
class extension capabilitiesGroups of functions, attributes, and attribute values that an instrument class specification defines to represent instrument class features that are more specialized than the features that the Base Class Capabilities represent. A driver implements an extension capability only if the instrument being controlled by the driver supports the specialized features of the particular extension capability group. For example, the IviScope specification defines extension capability groups for various trigger modes, such as glitch triggering and TV triggering. IVI class-compliant specific instrument drivers are not required to implement extension groups, but should implement all class extensions that the instrument hardware supports. For a complete description of the class extension capabilities for a particular class, refer to individual class specifications. Refer Section 2.6, Capability Groups, of IVI 3.1: Driver Architecture Specification, for more information on class extension capabilities at
coercionRefer to value coercion.


DLLDynamic Link Library
driverA software module that controls a hardware device. Also refer to IVI driver.
driver sessionA session for an IVI driver.
driver session configurationAn item you configure in MAX to associate an IVI driver with initial settings and possibly one or more hardware assets.


error codeA value returned by the instrument driver when execution does not successfully complete.
extension capabilityRefer to class extension capabilities.


.fp fileA file that contains information that allow the interactive program to display function panels that correspond to a specific instrument driver.
function panelA user interface in LabWindows™/CVI™ libraries that allows you to interactively execute library functions and to generate code for insertion in a program.
function treeThe hierarchical structure that defines the grouping of functions in an instrument driver.


GPIBGeneral Purpose Interface Bus. The common name for the communications interface system defined in ANSI/IEEE Standard 488.1-1987.


handleA unique identification that allows access to a session.
hardware assetA physical device or instrument that performs a measurement or stimulus function.
hardware configuration attributeAn attribute that allows the user to set and retrieve the value of an instrument setting.


I/O resource descriptorRefer to resource descriptor.
include fileA file that contains function declarations, constant definitions, and external declaration of global variables that the instrument driver exports.
initiateCause an instrument to begin an operation using one of the IVI Initiate functions.
inherent capabilitiesThe set of functions, attributes, and attribute values that all IVI drivers are required to implement.
instrumentA type of hardware asset.
instrument classA way to typify instruments. Instruments with common capabilities can be considered to be of the same class. For example, "Function Generator" is an instrument class typified by an ability to generate voltage signals.
instrument driver A set of routines designed to control an instrument, and a set of data structures to represent the driver.
instrument handleRefer to handle.
instrument interchangeabilityThe ability to exchange hardware assets in a test system with few or no changes to the test program.
instrument specific driver capabilitiesFunctions, attributes, and attribute values that represent features not defined by an instrument class specification. For example, some oscilloscopes have special features such as jitter and timing analysis, that are not defined in the IviScope class specification. The functions, attributes, and attribute values necessary to access the jitter and timing analysis capabilities of an oscilloscope are considered instrument specific driver capabilities. Instrument specific driver capabilities are beyond the scope of an instrument class.
IVIInterchangeable Virtual Instruments
IVI class driverAn IVI driver that exposes a class-compliant API and serves as a pass-through layer to IVI class compliant specific drivers. For example, an IviScope class driver exports the functions, attributes, and attribute values defined in the IviScope class specification. When an application program calls an IviScope class driver, the IviScope class driver calls an IVI class-compliant specific driver that communicates with an oscilloscope. IVI class drivers are necessary for instrument interchangeability when using IVI-C class-compliant specific drivers.
IVI class-compliant specific driverAn IVI specific driver that complies with one of the IVI class specifications. For example, an IVI class-compliant specific driver for an oscilloscope exports the API defined by the IviScope class specification. Typically, an IVI class-compliant specific driver also provides instrument specific driver capabilities.
IVI class specificationA specification that defines the standard set of interfaces for an instrument class.
IVI driverA software module that controls a hardware device and that complies with the IVI Foundation specifications. For IVI Foundation compliance requirements, refer to IVI-3.1: Driver Architecture Specification at
IVI driver installerAn IVI installer that installs IVI drivers.
IVI engineA support library for IVI instrument drivers that performs common tasks such as session creation, attribute management, and instrument status checking.
IVI LibraryRefer to IVI engine. The terms IVI engine and IVI Library are used interchangeably throughout IVI driver documentation and refer to the same software component.
IVI specific driverAn IVI driver that contains information for controlling a particular instrument or family of instruments and communicates directly with the instrument hardware. For example, IVI specific drivers control message-based instrument hardware by sending command strings and parsing responses.


LabVIEWLaboratory Virtual Instrument Engineering Workbench—a program development application based on the programming language G and used commonly for test and measurement purposes.
LabWindows/CVIADE for programming in ANSI C
logical nameThe name that you pass to identify the particular driver session that the IVI engine uses when you call a class driver initialize function. The driver session, in turn, identifies a particular specific driver and hardware asset and specifies the initial settings for the session. If you want to use your program with a different physical instrument, you change the properties of the logical name to use the driver session for the new instrument. You use MAX to create and edit logical names.


MAXRefer to Measurement & Automation Explorer.
Measurement & Automation ExplorerA controlled, centralized configuration environment that allows you to configure all your National Instruments devices.


NI I/O TraceAn application monitor for Windows applications that use National Instruments drivers. It can monitor, record, and display calls made to IVI class drivers. NI I/O Trace quickly locates any erroneous calls your application makes to the IVI class drivers.


physical identifierRefer to physical repeated capability identifier.
physical repeated capability identifierAn instrument specific driver string that refers to a particular instance of a repeated capability. An IVI specific driver that implements repeated capabilities defines the repeated capability identifiers that it recognizes.
published APIAn API that is designed for implementation across several software modules, and as such is published independently of any one software module that implements it. Examples are IVI instrument class APIs and IVI-MSS role APIs.


range checkingThe functionality of a driver that validates parameter and attribute values against published instrument limits. Range checking is a configurable behavior that can be enabled or disabled by the user.
repeated capabilityAn instrument capability for which multiple instances can be configured independently. Examples of repeated capabilities include channels on an oscilloscope, traces on a spectrum analyzer, and modulators on a RF signal generator.
repeated capability identifierA virtual or physical repeated capability identifier.
repeated capability nameThe name published by an IVI driver or class specification to refer to a particular repeated capability. For example, the IviScope class specification defines "Channel" as a repeated capability name.
resource descriptorA string, such as a VISA resource descriptor, that specifies the I/O address of a hardware asset.
resource nameRefer to resource descriptor.


sessionA run-time instance that provides context for communicating and interacting with a particular physical instrument or collection of physical instruments. For IVI drivers, a session maintains configuration information and instrument state information from one IVI driver call to another and across threads. The user creates a driver session by calling the Initialize function of the driver. When creating a session in an application program, the user may reference a session configuration from the IVI configuration store. The session ends when you close the driver.
session configurationAn item you configure in MAX to associate an instrument driver with initial settings and possibly one or more hardware assets.
simulationA required feature of IVI drivers that allows users to develop application code even when the instrument is not available. In simulation mode, the instrument driver does not perform I/O on the instrument.
simulation driversA set of routines that IVI class drivers use to implement simulation features. The IVI Compliance Package installs a simulation driver for each IVI class driver. Each simulation driver plugs in to the corresponding class driver and performs flexible simulation of data output.
simulation driver sessionA logical construct that identifies the simulation driver and its configuration. Simulation driver sessions reference simulation drivers instead of specific drivers. Simulation driver sessions do not reference a hardware asset.
specific driverRefer to IVI specific driver.
state cachingA behavior of IVI specific drivers that tracks the state of instrument settings at run time. When the user enables state caching on an IVI driver that implements state caching, the instrument driver performs instrument I/O only when the current state of an instrument setting is different from what the user requests. State caching can improve performance of a test program by preventing the driver from sending redundant commands to the instrument.
status codeAn error code or completion code.


value coercionOccurs when an IVI specific driver alters the value that the user specifies for an attribute or parameter to a value that the specific driver or instrument can accept. If the specific driver coerces an attribute value, the specific driver returns the coerced value when the user reads the value of the attribute. For attributes that represent a continuous range of values, a driver may coerce the value that the user requests to a value that is more appropriate for the instrument.
value parameterA scalar parameter of integer, single-precision, long, or double-precision data type whose value is not modified by the subroutine or function. In other words, an integer, single-precision, long, or double-precision scalar parameter is a value parameter if and only if its function panel control is not an output control.
virtual identifierRefer to virtual repeated capability identifier.
virtual repeated capability identifierAn alias the user defines in a driver session in the IVI configuration store to represent a physical repeated capability identifier. The IVI configuration store contains the mappings between virtual repeated capability identifiers and physical repeated capability identifiers. Users striving for instrument interchangeability should use virtual repeated capability identifiers in their application programs.
VI TreeThe hierarchical structure that defines the grouping of VIs in an instrument driver.
VISAVirtual Instrument Software Architecture. VISA provides an I/O API for communicating over a variety of bus interfaces, including GPIB, VXI, and serial interfaces.
VXIVMEbus Extensions for Instrumentation, or IEEE 1155.VME eXtensions for Instrumentation.
VXIplug&play Systems AllianceAn organization whose members share a common commitment to end-user success with open, multivendor test and measurement systems. To view specifications defined by this alliance, refer to


warning codeA value that an instrument driver returns after successful execution to provide additional information to the user. For example, if an instrument does not support a self test operation, calling the self test function will return a self test not supported code.


Not Helpful