HP Drive User Manual
Getting S tarted Guide
Your Guide to Getting
Started with IVI Drivers
Revision 1.0
Contents
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Chapter 1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Why Use an Instrument Driver?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Why IVI?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Why Use an IVI Driver? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Flavors of IVI Drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Shared Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Download and Install IVI Drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Familiarizing Yourself with the Driver. . . . . . . . . . . . . . . . . . . . . . . . . . .14
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Chapter 2 Using IVI with Visual C++. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
The Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Example Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Download and Install the Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Using IVI-COM in C++ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Create a New Project and Import the Driver Type Libraries. . . . . . . . . . 18
Initialize COM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Create an Instance of the Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Initialize the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Configure the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Set the Trigger Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Set the Reading Timeout/Display the Reading . . . . . . . . . . . . . . . . . . . 21
Error Checking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Close the Session . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Build and Run the Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Using IVI-C in Visual C++. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
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Create a New Project and Import the Driver Type Libraries. . . . . . . . . . 22
Declare Variables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Define Error Checking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Initialize the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Configure the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Set the Trigger and Trigger Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Set the Reading Timeout/Display the Reading . . . . . . . . . . . . . . . . . . . 26
Close the Session . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Build and Run the Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Further Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Chapter 3 Using IVI with Visual C# and Visual Basic .NET . . . . . . . . . . . . . . . 29
The Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Example Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Download and Install the Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Create a New Project and Reference the Driver . . . . . . . . . . . . . . . . . .30
Create an Instance of the Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Initialize the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Configure the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Set the Trigger Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Set the Reading Timeout/Display the Reading . . . . . . . . . . . . . . . . . . . 33
Close the Session . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Build and Run the Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Tips. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Further Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Chapter 4 Using IVI with LabVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
The Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
Example Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
Download and Install the Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Using IVI-C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
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Create a Project and Access the Driver. . . . . . . . . . . . . . . . . . . . . . . . . 38
Initialize the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Configure the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Take the Reading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
Display the Reading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
Close the Session . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Add Error Checking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
Run the Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Setting a Property in an IVI-C Driver . . . . . . . . . . . . . . . . . . . . . . . . . . .42
Using IVI-COM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Create a Project and Access the Driver. . . . . . . . . . . . . . . . . . . . . . . . . 42
Initialize the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Configure the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Take the Reading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
Display the Reading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
Close the Driver and Automation Sessions . . . . . . . . . . . . . . . . . . . . . .46
Add Error Checking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
Run the Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Further Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Chapter 5 Using IVI with LabWindows/CVI . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
The Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49
Example Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49
Download and Install the Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Create a New Project and Add Instrument Driver Files . . . . . . . . . . . . . 49
Initialize the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Configure the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Set the Reading Timeout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
Display the Reading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
Close the Session . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
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Further Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Chapter 6 Using IVI with MATLAB® . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
The Development Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Example Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
Download and Install the Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Configure the IVI Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Generate an Instrument Wrapper. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61
Configure and Control the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Create an Instance of the Instrument . . . . . . . . . . . . . . . . . . . . . . . 61
Connect to the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Configure the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61
Set the Trigger Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62
Set Reading Timeout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Display Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Disconnect from the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . .62
Remove the Driver from Memory . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Further Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Chapter 7 Using IVI with Measure Foundry®. . . . . . . . . . . . . . . . . . . . . . . . . . . 65
The Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65
Example Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65
Download and Install the Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Data Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Control Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Data Sink . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Compile and Run . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70
Close Session . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Further Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Chapter 8 Using IVI with PAWS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
The Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
Example Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
Download and Install the Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
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Prepare the PAWS Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Add the WCEM Interface Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . .76
Connect to the IVI-COM Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Build the Project. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Prepare the Run-Time System Environment . . . . . . . . . . . . . . . . . . . . .82
Load and Run the Project. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83
Further Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Chapter 9 Using IVI with Visual Basic 6.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
The Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85
Example Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85
Download and Install the Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Create a New Project and Reference the Driver . . . . . . . . . . . . . . . . . .85
Add a Button. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86
Create an Instance of the Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Initialize the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Configure the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Set the Trigger Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Display the Reading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
Close the Session . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Tips. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90
Further Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Chapter 10 Using IVI with Agilent VEE Pro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
The Development Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Example Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93
Download and Install the Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Launch the Instrument Manager and Select the Driver . . . . . . . . . . . . .93
Create an Instance of the Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Initialize the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Configure the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
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Set the Trigger Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Set the Reading Timeout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97
Close the Session . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Display the Reading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98
Tips. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98
Another Method to Display the Reading. . . . . . . . . . . . . . . . . . . . . 98
Further Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Chapter 11 Advanced Topics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
IVI Architecture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101
Driver API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Driver Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Instrument I/O. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
Shared Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .104
Interchangeability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
IVI Configuration Store. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .106
IVI-COM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .109
IIviDriver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
IIviDmm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
IVI-C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
Editing the Configuration Store. . . . . . . . . . . . . . . . . . . . . . . . . . . .112
Future Development of IVI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
IVI Drivers in Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .112
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Purpose
Chapter 1
Introduction
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Welcome to
IVI drivers and shows you how to create a short program to perform a
measurement. The guide also provides a brief introduction to several advanced
topics.
IVI Getting Started Guide
to control test-and-measurement instruments. As you develop test programs, you
face decisions about how you communicate with the instruments. Some of your
choices include Direct I/O, VXIplug&play drivers, or IVI drivers. If you are new to
using IVI drivers or just want a quick refresher on how to get started,
Started Guide
IVI Getting Started Guide
is intended for individuals who write and run programs
can help.
. This guide introduces key concepts about
IVI Getting
IVI Getting Started Guide
to-use tools. IVI drivers provide a number of advantages that can save time and
money during development, while improving performance as well. Whether you are
starting a new program or making improvements to an existing one, you should
consider the use of IVI drivers to develop your test programs.
So consider this the “hello, instrument” guide for IVI drivers. If you recall, the “hello
world” program, which originally appeared in Programming in C: A Tutorial, simply
prints out “hello, world.” The “hello, instrument” program performs a simple
measurement on a simulated instrument and returns the result. We think you’ll find
that far more useful.
Why Use an Instrument Driver?
To understand the benefits of IVI drivers, we need to start by defining instrument
drivers in general and describing why they are useful. An instrument driver is a set
of software routines that controls a programmable instrument. Each routine
corresponds to a programmatic operation, such as configuring, writing to, reading
from, and triggering the instrument. Instrument drivers simplify instrument control
and reduce test program development time by eliminating the need to learn the
programming protocol for each instrument.
shows you that IVI drivers can be straightforward, easy-
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Starting in the 1970s, programmers used device-dependent commands for
computer control of instruments. But lack of standardization meant even two digital
multimeters from the same manufacturer might not use the same commands. In
the early 1990s a group of instrument manufacturers developed Standard
Commands for Programmable Instrumentation (SCPI). This defined set of
commands for controlling instruments uses ASCII characters, providing some
basic standardization and consistency to the commands used to control
instruments. For example, when you want to measure a DC voltage, the
standard SCPI command is “MEASURE:VOLTAGE:DC?”.
In 1993, the VXIplug&play Systems Alliance created specifications for instrument
drivers called VXIplug&play drivers. Unlike SCPI, VXIplug&play drivers do not
specify how to control specific instruments; instead, they specify some common
aspects of an instrument driver. By using a driver, you can access the instrument
by calling a subroutine in your programming language instead of having to format
and send an ASCII string as you do with SCPI. With ASCII, you have to create and
send the instrument the syntax “
MEASURE:VOLTAGE:DC?
”, then read back a
string, and build it into a variable. With a driver you can merely call a function called
MeasureDCVoltage( ) and pass it a variable to return the measured voltage.
Although you still need to be syntactically correct in your calls to the instrument
driver, making calls to a subroutine in your programming language is less error
prone. If you have been programming to instruments without a driver, then you are
probably all too familiar with hunting around the programming guide to find the right
SCPI command and exact syntax.
You also have to deal with an I/O library to
format and send the strings, and then build the response string into a variable.
•
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10
Chapter 1
•
•
•
Why IVI?
The VXIplug&play drivers do not provide a common programming interface. That
means programming a Keithley DMM using VXIplug&play still differs from
programming an Agilent DMM. For example, the instrument driver interface for one
may be ke2000_read while another may be hp34401_get or something even
farther afield. Without consistency across instruments manufactured by different
vendors, many programmers still spent a lot of time learning each individual driver.
T o carry VXIplug&play drivers a step (or two) further, in 1998 a group of end users,
instrument vendors, software vendors, system suppliers, and system integrators
joined together to form a consortium called the Interchangeable Virtual Instruments
(IVI) Foundation. If you look at the membership, it’s clear that many of the
foundation members are competitors. But all agreed on the need to promote
specifications for programming test instruments that provide better performance,
reduce the cost of program development and maintenance, and simplify
interchangeability.
For example, for any IVI driver developed for a DMM, the measurement command
is IviDmmMeasurement.Read, regardless of the vendor. Once you learn how to
program the commands specified by IVI for the instrument class, you can use any
vendor’s instrument and not need to relearn the commands. Also commands that
are common to all drivers, such as Initialize and Close, are identical regardless of
the type of instrument. This commonality lets you spend less time hunting around
the help files and programming an instrument, leaving more time to get your job
done.
That was the motivation behind the development of IVI drivers.The IVI
specifications enable drivers with a consistent and high standard of quality,
usability , and completeness. The specifications define an open driver architecture,
a set of instrument classes, and shared software components. Together these
provide consistency and ease of use, as well as the crucial elements needed for
the advanced features IVI drivers support: instrument simulation, automatic range
checking,
state caching, and interchangeability
.
The IVI Foundation has created IVI class specifications that define the capabilities
for drivers for the following eight instrument classes:
Class IVI Driver
Digital multimeter (DMM) IviDmm
Oscilloscope IviScope
Arbitrary waveform/function generator IviFgen
DC power supply IviDCPwr
Switch IviSwitch
Power meter IviPwrMeter
Spectrum analyzer IviSpecAn
RF signal generator IviRFSigGen
IVI Class Compliant drivers usually also include capability that is not part of the IVI
Class. It is common for instruments that are part of a class to have numerous
functions that are beyond the scope of the class definition. This may be because
the capability is not common to all instruments of the class or because the
instrument offers some control that is more refined than what the class defines.
IVI also defines custom drivers. Custom drivers are used for instruments that are
not members of a class. For example, there is not a class definition for network
analyzers, so a network analyzer
driver must be a custom driver. Custom drivers
provide the same consistency and benefits described below for an IVI driver,
except interchangeability.
Introduction
•
•
•
11
•
•
•
IVI drivers conform to and are documented according to the IVI specifications and
usually display the standard IVI logo.
Note
: For more information on the types of IVI drivers, refer to Chapter 11,
Advanced Topics.
Why Use an IVI Driver?
Why choose IVI drivers over other possibilities? Because IVI drivers can increase
performance and flexibility for more intricate test applications. Here are a few of the
benefits:
Consistency
instrument. That saves you time when you
Ease of use
Development Environments (ADEs). The APIs provide fast, intuitive access to
functions. IVI drivers use technology that naturally integrates in many differen t
software environments.
– IVI drivers all follow a common model of how to control the
need to use a new instrument.
– IVI drivers feature enhanced ease of use in popular Application
•
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12
Chapter 1
•
•
•
Quality
–
IVI drivers focus on common commands, desirable options, and
rigorous testing to ensure driver quality.
Simulation –
IVI drivers allow code development and testing even when an
instrument is unavailable. That reduces the need for scarce hardware resources
and simplifies test of
measurement applications. The example programs in this
document use this feature.
Range checking –
IVI drivers ensure the parameters you use are within
appropriate ranges for an instrument.
State caching –
IVI drivers keep track of an instrument’s status so that I/O is only
performed when necessary, preventing redundant configuration commands from
being sent. This can significantly improve test system performance.
Interchangeability –
IVI drivers enable exchange of instruments with minimal
code changes, reducing the time and effort needed to integrate measurement
devices into new or existing systems. The IVI class specifications provide syntactic
interchangeability but may not provide behavioral interchangeability.
In other
words, the program may run on two different instruments but the results may
not be the same due to differences in the way the instrument itself functions.
Flavors of IVI Drivers
To support all popular programming languages and development environments,
IVI drivers provide either an IVI-C or an IVI-COM (Component Object Model) API.
Driver developers may provide either or both interfaces, as well as wrapper
interfaces optimized for specific development environments.
Although the functionality is the same,
C development environments; IVI-COM drivers are optimized for environment s
that support the
VXIplug&play driver specification and their usage is similar. IVI-COM drivers
provide easy access to instrument functionality through methods and properties.
All IVI drivers communicate to the instrument through an I/O Library. Our examples
use the Virtual Instrument Software Architecture (VISA), a widely used standard
library for communicating with instruments from a personal computer.
Shared Components
To make it easier for you to combine drivers and other software from various
vendors, the IVI Foundation members have cooperated to provide common
software components, called IVI Shared Components. These components provide
services to drivers and driver clients that need to be common to all drivers. For
instance, the IVI Configuration Server enables administration of system-wide
configuration.
Important! You must install the IVI Shared Components before an IVI driver
can be installed.
The IVI Shared Components can be downloaded from vendors’ web sites as well
as from the IVI Foundation Web site.
To download and install shared components from the IVI Foundation Web site:
1 Go to the IVI Foundation Web site at http://www.ivifoundation.org.
2 Locate Shared Components.
3 Choose the IVI Shared Components msi file for the Microsoft Windows
Installer package or the IVI Shared Components exe for the executable
installer.
IVI-C drivers are optimized for use in ANSI
Component Object Model (COM). IVI-C drivers extend the
Download and Install IVI Drivers
After you’ve installed Shared Components, you’re ready to download and install an
IVI driver. For most ADEs, the steps to download and install an IVI driver are
identical. For the few that require a different process, the relevant chapter in
Getting Started Guide
IVI Drivers are available from your hardware or software vendor’s web site or by
linking to them from the IVI Foundation web site.
provides the information you need.
IVI
Introduction
•
•
•
13
•
•
•
To see the list of drivers registered with the IVI Foundation, go to
http://www.ivifoundation.org
Familiarizing Yourself with the Driver
Although the examples in
likely
employ a variety of IVI drivers
task, you’ll want to familiarize yourself quickly with drivers you haven’t used before.
Most ADEs provide a way to explore IVI drivers to learn their functionality. In each
chapter, where applicable, we add a note explaining how to view the available
functions. In addition, browsing an IVI driver’s help file often proves an excellent
way to learn its functionality.
Examples
As we noted above, each example chapter in
you how to use an IVI driver to write and run a program that performs a simple
measurement on a simulated instrument and returns the result. The examples
demonstrate common steps using IVI drivers.
includes the steps listed below:
•
Download and Install the IVI driver– covered in the Download and Install IVI
Drivers section above.
•
Determine the VISA address string – Examples in
use the simulate mode, so we chose the address string
often shown as GPIB::23. If you need to determine the VISA address string for
your instrument and the ADE does not provide it automatically, use an IO
application, such as National Instruments Measurement and Automation
Explorer (MAX) or Agilent Connection Expert.
•
Reference the driver or load driver files – For the examples in this guide, the
driver is the
March 2006 (from Agilent Technologies)
Specific driver, Version 4.1, October 2006 (from National Instruments).
•
Create an instance of the driver in ADEs that use COM – For the examples in
this guide, the driver is the
•
Write the program:
•
Agilent 34401A IVI-COM Specific Driver, Version 1.1.0.11,
Initialize the instrument – Initialize is required when using any IVI driver.
Initialize establishes a communication link with the instrument and must
be called before the program can do anything with the instrument. We set
reset to
true
, ID query to
.
IVI Getting Started Guide
to develop test programs. To jumpstart that
Agilent 34401A (IVI-COM) or HP 34401 (IVI-C)
false
, and simulate to
use a DMM driver, you will
IVI Getting Started Guide
Where practical, every example
IVI Getting Started Guide
GPIB0::23::INSTR,
or the
Agilent 34401A IVI-C
true
.
shows
.
•
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14
Chapter 1
•
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•
Setting reset to true tells the driver to initially reset the instrument.
Setting the ID query to false prevents the driver from verifying that the
connected instrument is the one the driver was written for. Finally,
setting simulate to true tells the driver that it should not attempt to
connect to a physical instrument, but use a simula tio n of the
instrument.
•
Configure the instrument – We set a range of
0.001 volts (1 millivolt)
.
1.5 volts
and a resolution of
•
Access an instrument property – We set the trigger delay to
seconds
•
Set the reading timeout – We set the reading timeout to
milliseconds (1 second).
•
Take a reading
•
Close the instrument – This step is required when using any IVI driver,
unless the ADE explicitly does not require it. We close the session to free
resources.
Important! Close may be the most commonly missed step when using an
IVI driver. Failing to do this could mean that system resources are not
freed up and your program may behave unexpectedly on subsequent
executions.
•
Check the driver for any errors.
•
Display the reading.
Note:
Examples that use a console application do not show the display.
Now that you understand the logic behind IVI drivers, let’s see how to get started.
.
0.01
1000
Introduction
•
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15
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16
Chapter 1
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•
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Chapter 2
Using IVI with Visual C++
• • • • • •
The Environment
Microsoft Visual C++ is a software development environment for the C++
programming language and is available as part of Microsoft Visual Studio.
Visual C++ allows you to create, debug, and execute conventional applications
as well as applications that target the .NET Framework.
Example Requirements
•
Visual C++
•
Microsoft Visual Studio 2005
•
IVI-COM: Agilent 34401A IVI-COM, Version 1.1.0.11, March 2006 (from Agilent
Technologies); or
•
IVI-C: Agilent 34401A IVI-C, Version 4.1, October 2006 (from National
Instruments)
•
Agilent IO Libraries Suite 14.2
Download and Install the Driver
If you have not already installed the driver, go to the vendor W eb site and follow the
instructions to download and install it.
Since Visual C++ supports both IVI-COM and IVI-C drivers, this example is written
two ways, first to show how to use an IVI-COM driver in Visual C++, and second to
show how to use an IVI-C driver in Visual C++.
Note
because the referenced files are not included in the program. If you need to
download and install a driver, you do not need to exit V isual Studio. Install the driver
and continue with your program.
Using IVI-COM in C++
The following sections show how to get started with an IVI-COM driver in Visual
C++
: If you do not install the appropriate instrument driver , the project will not build
•
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17
•
•
•
Create a New Project and Import the Driver Type Libraries
To use an IVI Driver in a Visual C++ program, you must provide the path to the
driver DLL.
•
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•
18
Chapter 2
•
•
•
1 Launch Visual Studio 2005 and create a Win32 Console Application in C++
with the name IVI demo.
Note:
The program already includes some required code, including the header file
#include stdafx.h
.
2 From the Tools menu select Options.
3 Expand “Projects and Solutions”, then click on “VC++ Directories”
4 Click on the “Show directories for” combo box and choose “Library files”
5 Add the following two entries to your path.
The first entry will point to the default directory for IVI drivers. This is typically:
“C:\Program Files\Ivi\Bin”
The second entry points to the VISA DLL that many drivers require:
Initialize COM
“$(VXIPNPPATH)VisaCom”
Note:
These steps need only be done once for each computer you use. All
subsequent Visual Studio projects will continue to use these settings and will be
able to locate your IVI-COM drivers.
6 Click OK
7 To import the type libraries, type the following statements following the header
file reference:
#import “IviDriverTypeLib.dll” no_namespace
#import “IviDmmTypeLib.dll” no_namespace
#import “GlobMgr.dll” no_namespace
#import “Agilent34401.dll” no_namespace
Note:
The
import
statements access the driver type libraries used by the Agilent
34401 DMM. The no_namespace attribute allows the code to access the interfaces
in the typelibraries from the global namespace.
1 To initialize the COM library, type the following lines after the { following the int
statement:
HRESULT hr;
hr = CoInitialize(NULL);
IF(FAILED(hr))
exit(1);
Note: Including error handling in your programs is good practice. This code
checks for errors in your program.
2 To close the COM library before exiting, type the following line at the end of
your code, right before the return line:
CoUninitialize();
Create an Instance of the Driver
To create an instance of the driver, type
IIviDmmPtr dmm(__uuidof(Agilent34401));
Note:
This creates a smart pointer that provides easy access to the COM object.
You are now ready to write the program to control the simulated instrument.
Using IVI with Visual C++
•
•
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19
•
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•
Initialize the Instrument
You can now write the main constructs for your program.
Below the smart pointer statement, type
dmm->Initialize("GPIB::23", false, true, "simulate=true");
Note
: As soon as you type ->, Intellisense displays options and helps ensure you
use correct syntax and values.
Configure the Instrument
To set the range to 1.5 volts and resolution to 0.001 volts, type
dmm->Configure(IviDmmFunctionDCVolts, 1.5, 0.001);
•
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20
Chapter 2
•
•
•
Set the Trigger Delay
To set the trigger delay to 0.01 seconds, type
dmm->Trigger->Delay = 0.01;
Set the Reading Timeout/Display the Reading
Create a variable to represent the reading and make a reading with a timeout of 1
second (1000 milliseconds).
1 Type
double reading = dmm->Measurement->Read(1000);
2 To display the reading, use printf. Type
wprintf(L“Reading: %g\n”, reading);
Error Checking
To catch errors in the code, activate error checking.
1 Surround the preceding statement s with a try block. Add the following lines as
shown in the illustration above:
try {
}
2 Process errors in a catch block. Type
catch (_com_error e) {
wprintf(L“Error: %s”, e.ErrorMessage());
}
Close the Session
To close out the instance of the driver and free resources, type
dmm->Close();
The final code should look like the following:
#include "stdafx.h"
#import "IviDriverTypeLib.dll" no_namespace
#import "IviDmmTypeLib.dll" no_namespace
#import "GlobMgr.dll" no_namespace
#import "Agilent34401.dll" no_namespace
int IVI_Demo()
{
HRESULT hr;
hr = CoInitialize(NULL);
if(FAILED(hr))
Using IVI with Visual C++
•
•
•
21
•
•
•
exit(1);
{
IAgilent34401Ptr dmm(__uuidof(Agilent34401));
try{
dmm->Initialize("GPIB::23",false,true,"simulate=true");
dmm->DCVoltage->Configure(1.5, 0.001);
dmm->Trigger->Delay = 0.01;
double reading = dmm->Measurement->Read(1000);
wprintf(L“Reading: %g\n”, reading);
}
catch(_com_error e){
wprintf(L“Error: %s\n”, e.ErrorMessage);
}
dmm->Close();
}
CoUninitialize();
return 0;
}
•
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22
Chapter 2
•
•
•
Build and Run the Application
Build your application and run it to verify it works properly.
1 From the Start Menu, select Build, and click Build IVIDemo.
2 From the Start Menu, select Debug, and run the application.
Using IVI-C in Visual C++
The following sections show to get started with IVI-C in Visual C++.
Create a New Project and Import the Driver Type Libraries
To use an IVI-C Driver in a Visual C++ program, you must provide paths to the
header files and libraries it uses.
1 Launch Visual Studio 2005 and create a Win32 Console Application in C++
with the name IVI demo.
Note:
The program already includes some required code, including the header file
#include stdafx.h
.
2 From the Tools menu select Options.
3 Expand “Projects and Solutions”, then click on “VC++ Directories”
4 Click on the “Show directories for” combo box and choose “Library files”
5 Add the following entry to your “Library files” path.
This entry points to the default directory for IVI drivers. This is typically:
“C:\Program Files\IVI\Lib\msc”
6 Click on the “Show directories for” combo box and choose “Include files”
7 Add the following entries to your “Include files” path.
The first entry will point to the default directory for IVI drivers. This is typically:
“C:\Program Files\IVI\include”
The second entry points to the VISA header files that IVI-C drivers require:
“$(VXIPNPPATH)WinNT\include”
8 Click OK
Note:
These initial steps need only be done once for each computer you use. All
subsequent Visual Studio projects will continue to use these settings and will be
able to locate your IVI-COM drivers.
9 Select Project and click Properties. The IVIDemo.cpp “Property pages” dialog
box appears.
Using IVI with Visual C++
•
•
•
23
•
•
•
10 Expand “Configuration Properties”
11 Expand “Linker”
12 Select Input. In the Additional Dependencies field, type
13 Select OK.
14 To add the hp34401a instrument driver header file to your program, type the
15 From the Main Menu, select Build and click Build IVIDemo.
Declare V ariables
1 Y ou will need to declare some variables that will be used in your program. T ype
“hp34401a.lib”
following statement following the existing header file reference:
#include “hp34401a.h”
the following lines after the { in the int main () statement:
ViSession session;
ViStatus error = VI_SUCCESS;
ViReal64 reading;
•
•
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24
Chapter 2
•
•
•
Define Error Checking
1 Next define error checking for your program. First you will define a macro to
catch the errors. It is better to define it once at the beginning of the program
that to add the logic to each of your program statements. After the #include
statements, type the following lines:
#ifndef checkErr
#define checkErr(fCall) \
if (error = (fCall), (error = (error < 0) ? \
error : VI_SUCCESS)) \
{goto Error;} else error = error
#endif
2 Next you will type the following lines at the end of the program to handle any
errors that occur:
Error:
if (error != VI_SUCCESS)
{
ViChar errStr[2048];
hp34401a_GetError (session, &error, 2048, errStr);
printf ("Error!", errStr);
}
Note: Including error handling in your programs is good practice. This code checks
for errors in your program.
Initialize the Instrument
1 To initialize the instrument, add the following Initialize with Options function
right after the variable declarations you added in the previous section
checkErr( hp34401a_InitWithOptions (“GPIB::23::INSTR”,
This initializes the instrument with the following parameters:
• GPIB0::23::INSTR as the Resource Name (instrument at GPIB address 23)
• VI_FALSE Does not perform an ID Query
• VI_TRUE Resets the device
VI_FALSE, VI_TRUE, “Simulate = 1”, &session));
Using IVI with Visual C++
•
•
•
25
•
•
•
• Simulate=1 in the Options parameter sets the driver to simulation mode
• &session assigns the Instrument Handle to the variable “session” defined above
Configure the Instrument
1 To set the range to 1.5 volts and resolution to 0.001 millivolts, type:
checkErr( hp34401a_ConfigureMeasurement (session,
HP34401A_VAL_DC_VOLTS, 1.5, 0.001));
Set the Trigger and Trigger Delay
1 To set the trigger source to immediate and the trigger delay to 0.01 seconds,
type:
checkErr( hp34401a_ConfigureTrigger (session,
HP34401A_VAL_IMMEDIATE, 0.01));
Set the Reading Timeout/Display the Reading
1 To take a reading from the instrument and to set the reading timeout to 1
second (1000 ms) type:
checkErr( hp34401a_Read (session, 1000, &reading);
Note: The Read function takes a reading from the instrument and assigns the result
to the variable “reading” defined above.
2 To display the reading, use a pr int f statemen t. Type
printf (“Reading = %f”, reading);
•
•
•
26
Chapter 2
•
•
•
Close the Session
To close out the instance of the driver and free resources, type
If (session)
hp34401a_Close(session);
The final code should contain the code below:
#include "stdafx.h"
#include <hp34401a.h>
#ifndef checkErr
#define checkErr(fCall) \
if (error = (fCall), (error = (error < 0)?
error : VI_SUCCESS)) \
{goto Error;} else error = error
#endif
int main(int argc, _TCHAR* argv[])
{
ViSession session;
ViStatus error = VI_SUCCESS;
ViReal64 reading;
checkErr( hp34401a_InitWithOptions ("GPIB::23::INSTR",
VI_FALSE, VI_TRUE, "Simulate=1", &session));
checkErr( hp34401a_ConfigureMeasurement (session,
HP34401A_VAL_DC_VOLTS, 1.5, 0.0001));
checkErr( hp34401a_ConfigureTrigger (session,
HP34401A_VAL_IMMEDIATE, 0.01));
checkErr( hp34401a_Read (session, 1000, &reading));
printf ("Reading = %f", reading);
Error:
if (error != VI_SUCCESS)
{
ViChar errStr[2048];
hp34401a_GetError (session, &error, 2048, errStr);
printf ("Error!", errStr);
}
if (hp34401a)
hp34401a_close (hp34401a);
}
Build and Run the Application
Build your application and run it to verify it works properly.
Using IVI with Visual C++
•
•
•
27
•
•
•
1 From the Start Menu, select Build, and click Build IVI Demo.
2 From the Start Menu, select Debug, and run the application.
Further Information
Learn more about Visual C++ at http://msdn.microsfot.com/visualc/.
Microsoft® and Visual Studio® are registered tradem arks of Microsoft Corporation
in the United States and/or other countries.
•
•
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28
Chapter 2
•
•
•
Chapter 3
Using IVI with Visual C# and
Visual Basic .NET
• • • • • •
The Environment
C# and Visual Basic are object-oriented programming languages developed by
Microsoft. They enable programmers to quickly build a wide range of applications
for the Microsoft .NET platform. This chapter provides detailed instructions in C#
as well as the code for Visual Basic.
Visual Basic 6.0, refer to Chapter 9.
Note:
One of the key advantages of using C# and Visual Basic in the Microsoft®
Visual Studio
InstelliSense is a form of autocompletion for variable names and functions and a
convenient way to access parameter lists and ensure correct syntax. The feature
also enhances software development by reducing the amount of keyboard input
required.
Example Requirements
•
Visual C#
•
Microsoft Visual Studio 2005
•
Agilent 34401A IVI-COM, Version 1.1.0.11, March 2006 (from Agilent
Technologies)
•
Agilent IO Libraries Suite 14.2
®
Integrated Development Environment is IntelliSense™.
If you are looking for an example using
Download and Install the Driver
If you have not already installed the driver, go to the vendor W eb site and follow the
instructions to download and install it. You can also refer to Chapter 1, Download
and Install IVI Drivers, for instructions.
This example uses an IVI-COM driver. IVI-COM is the preferred driver for C#, but
IVI-C is also supported.
•
•
•
29
•
•
•
Create a New Project and Reference the Driver
To use an IVI Driver in a Visual C# program, you must first add a reference to it.
1 Launch Visual Studio and start a new Console Application in Visual C#.
Note:
The program already includes some required code, including using
statements. Keep this required code.
2 Select Project and click Add Reference. The Add Reference dialog appears.
3 Select the COM tab. All IVI drivers begin with IVI. Scroll to the IVI section and
select IVI Agilent 34401 (Agilent Technologies) 1.1 Type Library. Click OK.
Note
: If you have not installed the IVI driver, it will not appear in this list. You must
close the Add Reference dialog, install the driver, and select Add Reference again
for the driver to appear.
•
•
•
30
Chapter 3
•
•
•
Note:
The program looks the same as it did before you added the reference, but
the driver is now available for use. To see the reference, select View and click
Solution Explorer. Solution Explorer appears and lists the reference.
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