Delivering Interchangeability and More

Report
Delivering Interchangeability and More
AUTOTESTCON 2012
Anaheim, CA
September 10-13, 2012
Agenda
IVI Basics and Background
 IVI Architecture
 IVI Shared Components
 Why IVI?
 IVI-COM, IVI.NET and IVI-C

www.ivifoundation.org
IVI Background

Open consortium
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End-users
System integrators
Instrument and software vendors
Founded in August 1998, incorporated in March 2001
26 member companies
Consolidated home for many SW standards
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IVI Instrument Drivers
VISA
VXIplug&play
SCPI
LXI Synchronization
www.ivifoundation.org
What is IVI?
The primary purpose of the Consortium is to
• Promote the development and adoption of
standard specifications for programming test
instrument
• Focus on the needs of the people that use and
develop test systems who must take off-the-shelf
instrument drivers and build and maintain highperformance test systems
• Build on existing industry standards to deliver
specifications that simplify interchanging
instruments and provide for better performing and
more easily maintainable programs
From IVI Foundation By-laws
www.ivifoundation.org
IVI’s Fit with Other Specs
IVI 4.x(Classes)
Scope
DMM
FGen
DCPwr
ACPwr
Swtch
PwrMe
SpecAn
RFSigGn
Counter
DownCnv
UpConv
Digitiz
Instrument
Capabilities
Programming
Interfaces for
C/C++/C#/VB
LabVIEW, etc
IVI 3.x (Arch)
SCPI
C
COM
VXI
plug&play
.NET
VISA
message
register
IO Interfaces &
SW Protocols
IVI 6.3 PXI plug-in
HiSLIP
PXI-2 and PXI-6:
Software AXIe 2.0
VXI-11
GPIB
LXI
USB
TMC
GPIB
Ethernet
USB
VXI
VME
PXI
AXIe
1.0
PCI, PCIe &
Compact PCI
AXIe
3.1
T&M Specific
Needs
Physical
Connection
IVI’s Fit with Other Specs
IVI 4.x(Classes)
Scope
DMM
FGen
DCPwr
ACPwr
Swtch
PwrMe
SpecAn
RFSigGn
Counter
DownCnv
UpConv
Digitiz
Instrument
Capabilities
Programming
Interfaces for
C/C++/C#/VB
LabVIEW, etc
IVI 3.x (Arch)
SCPI
C
COM
VXI
plug&play
.NET
VISA
message
register
IO Interfaces &
SW Protocols
IVI 6.3 PXI plug-in
HiSLIP
PXI-2 and PXI-6:
Software AXIe 2.0
VXI-11
GPIB
LXI
USB
TMC
GPIB
Ethernet
USB
VXI
VME
PXI
AXIe
1.0
PCI, PCIe &
Compact PCI
AXIe
3.1
T&M Specific
Needs
Physical
Connection
What is IVI – Really??
4.15Digitizer
4.14 UpConv
4.13DownCnv
4.12 Counter
4.10RFSigGn
4.8 SpecAn
4.7 PwrMe
4.6 Swtch
4.5 ACPwr
4.4 DCPwr
4.1 Scope

4.3 FGen

Architecture specifications
Instrument class specifications
A library of shared software components
4.2 DMM

Architecture Specifications
3.1,3.2,3.3,3.4,3.5,3.6,3.9,.3.10,3.12,3.17,3.18
www.ivifoundation.org
13 specs @ ~220 pages
~1140 pages of specs
Goals of the IVI Foundation

Hardware Interchangeability

Simplify replacing an instrument from a system with a similar one
 Preserve test software when instruments become obsolete
 Simplify test code reuse from design validation to production test

Quality

Improve driver quality
 Establish guidelines for driver testing and verification

Software Interchangeability

Provide an architectural framework that allows users to easily integrate
software from multiple vendors
 Provide standard access to driver capabilities such as simulation, state
caching, range checking and coercion
 Provide consistent instrument control in popular programming
environments
www.ivifoundation.org
IVI Membership Benefits


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Influence the development of standards
Participate in and access future standards
Share ideas with developers, users, system
integrators and vendors
Access source code for shared components
Participate in interoperability sessions
Network with test and measurement industry
leaders
www.ivifoundation.org
Approved Instrument Classes
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DC power supply
AC power supply
DMM
Function generator
Oscilloscope
Power meter
RF signal generator
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Spectrum analyzer
Switch
Upconverter
Downconverter
Digitizer
Counter/timer
www.ivifoundation.org
Driver Architecture Spec’s
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IVI-3.1: Driver Architecture Specification
IVI-3.2: Inherent Capabilities Specification
IVI-3.3: Standard Cross-Class Capabilities Specification
IVI-3.4: API Style Guide
IVI-3.5: IVI Configuration Server Specification
IVI-3.6: COM Session Factory Specification
IVI-3.9: C Shared Components
IVI-3.12: Floating Point Services Specification
IVI-3.14: Primary Interop Assembly Specification
IVI-3.15: IviLxiSync Specification
IVI-3.17: Installer Requirements Specification
IVI-3.18: IVI.NET Utility Classes and Interfaces Specification
www.ivifoundation.org
IVI Driver Features

Simulation
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State caching
Range checking
Coercion


Required of all IVI drivers
Very useful for testing in new ADEs
Helpful when instruments are difficult to procure
Coercion recording
All extended features enabled and accessed in a
standard fashion
www.ivifoundation.org
IVI Shared Components
C Shared Components
 Floating Point Services
 IVI-COM Session Factory
 Configuration Server
 COM Type Libraries
 .NET PIAs
 IVI.NET Shared Components

www.ivifoundation.org
IVI Conformance

Basic conformance

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Follows all architecture specs
Implements inherent capabilities defined in IVI-3.2.
Not one of the classic instrument types
No class-compliant functionality (none of the IVI-4.X specs apply)
Can be advertised as fully IVI compliant
Instrument-class conformance

Basic conformance + one or more instrument class APIs (IVI-4.X
specs)
www.ivifoundation.org
What is IVI Compliant -Really??
Standard install location and process
 Support for IVI Features
 Common API for common tasks

 ~40
common functions
 Simulation,
Caching, Open, Close, Initialize, SW
Trigger, Status check, Version check …..

Consistent API
 Common
types, Name generation,
Organization
www.ivifoundation.org
What is IVI Class Compliant Really??
Adds Class Compliant API
 Instrument API same as other instruments
 Custom API still available

 Especially

for capabilities beyond the class
Simplifies swapping instruments
IVIFoundation.org
ww.ivifoundation.org
Why IVI – One Driver to Rule
them All


Much more than interchangeability
Arguably the biggest benefit is the ability to provide one
driver and give users a first class experience in nearly
all ADEs
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Visual Basic 6
Visual C++
Visual C# and Visual Basic.NET
VBA (Excel, Word, PowerPoint)
MATLAB
LabVIEW
LabWindows/CVI
Agilent VEE
www.ivifoundation.org
Why IVI? – Uniform Way of
Doing Common Tasks

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Avoids frustrations of arbitrary differences
Instantiation, initialization, shutdown
Controlling driver features – state caching, error query,
simulation, etc.
Configuration and installation
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Standard mechanism for handling multi-channel devices

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aka repeated capabilities in IVI parlance
Standard error reporting

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No need to dig thru header files, registry settings, help or readme
One place to reliably set the I/O address is a big benefit
No need to deal with the numerous possible error schemes
Versioning standards
www.ivifoundation.org
Why IVI – Tools, Tools, Tools

Far easier to develop an IVI driver with a tool than it is to
develop a customer driver without a tool

Common requirements enable tools

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Leads to better, cheaper drivers
Driver is much more than a DLL w/ function exports
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Help files
Installer
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IVI 3-17 dedicated to IVI installers and is 53 pages
Regression test apps / Unit test apps
Special components for .NET
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XML IntelliSense file
interop assembly
version policy files
www.ivifoundation.org
Why IVI – Tracking the
Standards

Vendors relieved from onerous task of keeping pace with
multiple moving targets
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Windows OSs, Windows help, Windows installer, Windows API,
security, .NET platform
Six versions of Visual Studio since IVI
Vista and UAC was a major challenge for IVI
64-bit OS support took two years within IVI
IVI member companies bring experts to meetings to ensure
IVI solutions work with their hardware

Users of IVI directly leverage R&D efforts of NI, Agilent, R&S, etc.
www.ivifoundation.org
API Standards in IVI

IVI specifications layout three APIs

IVI .NET
 IVI-COM
 IVI-C

Many considerations for both driver developers and end
users when choosing which technology to use

Driver developer environment
 Custom environment
 Others…(more on this later)

IVI specs also define how to build driver wrappers

Allows one code base while supporting IVI-C, IVI-COM and IVI .NET
APIs
 IVI-COM on top of IVI-C (not common)
 IVI-C on top of IVI-COM (very common in today’s IVI drivers)
www.ivifoundation.org
Simple IVI-COM Driver Usage
in Visual Basic
Dim driver as New Agilent54600
Dim scope as IIviScope
Set scope = driver
scope.Initialize “GPIB::10”, False, False, “”
scope.Trigger.Level = 3.4
scope.Trigger.Type = IviScopeTriggerEdge
‘setting a numeric property
‘setting an enum property
scope.Measurements.Initiate
‘calling a method
scope.Close
www.ivifoundation.org
Simple IVI-C Driver Usage
// NOTE: Error checking not shown
#include “ag54600.h”
int _tmain(int argc, _TCHAR* argv[])
{
ViSession vi;
ViStatus viStatus = ag54600_init(“GPIB::10”, VI_FALSE, VI_FALSE, &vi);
viStatus = ag54600_SetAttributeViReal64(vi, “”,
AG54600_ATTR_TRIGGER_LEVEL, 3.2);
viStatus = ag54600_SetAttributeViInt32(vi, “”,
AG54600_ATTR_TRIGGER_TYPE, AG54600_VAL_EDGE_TRIGGER);
viStatus = ag54600_InitiateAcquisition();
viStatus = ag54600_close();
}
www.ivifoundation.org
Motivations for IVI.NET


Present an API more suited to .NET developers
Simplify source code

Allow end users to understand instrument behavior by examining driver
source
 Allow end users to fix bugs on their own
 Allow end users to add features to drivers on their own

Richer, more expressive APIs

More flexibility with API data types
 Clean handling of asynchronous notifications (aka “events”)

Side-by-side deployment of drivers

Only one version of an IVI-COM or IVI-C driver can be installed at a
time
 IVI.NET allows multiple versions of a driver to be installed
www.ivifoundation.org
Richer Type System in IVI.NET

Both IVI-COM and IVI-C drivers suffer from a limited set of data
types

Integers, floats, Booleans, strings
 Arrays of the above, but extra parameters are required in IVI-C


IVI-C cannot expose an array of strings
IVI-C cannot expose structs

Can be done in IVI-COM, but it’s tedious to implement
IviScope_FetchWaveform(ViSession vi,
ViConstString channel,
ViInt32 waveformSize,
// # of elements on input
ViReal64 waveform[],
// actual data buffer
ViInt32 *actualPoints,
// # of elements on output
ViReal64 *initialX,
ViReal64 *xIncrement);
www.ivifoundation.org
Simplifying APIs with .NET Types
IVI-C signature
IviDigitizer_FetchWaveformReal64(ViSession Vi,
ViConstString ChannelName,
ViInt64 WaveformArraySize,
ViReal64 WaveformArray[],
ViInt64* ActualPoints,
ViInt64* FirstValidPoint,
ViReal64* InitialXOffset,
ViReal64* InitialXTimeSeconds,
ViReal64* InitialXTimeFraction,
ViReal64* XIncrement);
IVI.NET signature
Channels[].Measurement.FetchWaveform(IWaveform<Double> waveform)
www.ivifoundation.org
Simplified Usage Syntax

Simplified access to very commonly used features


Enums
Repeated capabilities (e.g. “channels”)
C# client using IVI-COM driver through interop
digitizer.Arm.Sources.get_Item("LAN3").Detection =
IviLxiSyncArmSourceDectionEnum.IviLxiSyncArmSourceDetectionHigh;
C# client using IVI.NET driver
digitizer.Arm.Sources["LAN3“].Detection = ArmSourceDetection.High;
www.ivifoundation.org
Shared IVI.NET Data Types

IVI Foundation felt it would be useful to offer commonly used data types as
part of the IVI.NET Shared Components

Increase consistency amongst IVI.NET drivers
 Facilitate data interchange between drivers

Standardized IWaveform and ISpectrum interfaces

Digitizers and scopes and RF spectrum analyzers all read waveforms
 Function generators and RF signal generators source waveforms
 Without a common definition of a “waveform”, client applications would need to
write the tedious code to translate between each class’s notion of a waveform

Time-based parameters can use PrecisionDateTime and
PrecisionTimeSpan

No confusion about ms vs sec, absolute vs relative time, UTC time, etc
 Precision adequate for IEEE 1588 devices

Common trigger source data type

Useful in “stitching” together devices in triggered source-measure operations
www.ivifoundation.org
Additional Information

For more information or to join, go to our webpage at:
www.ivifoundation.org

Additional Resources:

IVI Getting Started Guide on our Home page or Resources page



Either in in short pdf files for the ADE that you prefer
Or, single pdf file that includes eight different ADEs
Tutorial Videos Coming Soon: IVI Getting Started Guide
tutorial videos in the ADE you prefer.
www.ivifoundation.org

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