Getting Started with IVI Drivers Your Guide to Using IVI with Agilent VEE Pro Version 1.
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Contents •••••• Chapter 1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Why Use an Instrument Driver? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Why IVI?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Why Use an IVI Driver? . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 1 Introduction •••••• Purpose Welcome to Getting Started with IVI Drivers: Your Guide to Using IVI with Agilent VEE Pro. This guide introduces key concepts about IVI drivers and shows you how to create a short program to perform a measurement. The guide is part of the IVI Foundation’s series of guides, Getting Started with IVI Drivers. Getting Started with IVI Drivers is intended for individuals who write and run programs to control test-and-measurement instruments.
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.
the type of instrument. This commonality lets you spend less time browsing through the help files in order to program 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.
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. IVI drivers conform to and are documented according to the IVI specifications and usually display the standard IVI logo.
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 IVI-COM (Component Object Model) API.
IVI Drivers are available from your hardware or software vendor’s web site or by linking to them from the IVI Foundation web site. 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 Getting Started with IVI Drivers use a DMM driver, you will likely employ a variety of IVI drivers to develop test programs.
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 simulation of the instrument. • Configure the instrument – We set a range of 1.5 volts and a resolution of 0.001 volts (1 millivolt). • Access an instrument property – We set the trigger delay to 0.01 seconds.
Chapter 2 Using IVI with Agilent VEE Pro •••••• The Development Environment Agilent Visual Engineering Environment Pro is a graphical programming environment designed to help you quickly create and automate measurements and tests. VEE Pro lets you program by creating an intuitive block diagram. You select and edit objects from pull-down menus and connect them to specify the program flow. VEE Pro also includes Instrument Manager, which facilitates control and management of your devices.
• 0 in the Board Number field • GPIB0::23::INSTR in the VISA Address field 5 6 Click Advanced. The Advanced Instrument Properties dialog box appears. Click the IVI-COM Driver tab. Select Agilent 34401 from the drop-down list. Note: The VISA address that you entered earlier appears automaticaly in the Address field.
7 Click the IVI-COM Driver tab. Select Agilent 34401 from the drop-down list. Note: The VISA address that you entered earlier appears automatically in the Address field. 8 9 Click OK. The dialog closes and returns to the Instrument Properties dialog. Click OK. The dialog closes and returns to the Instrument Manager. Congratulations! You can now access the IVI Driver in the Instrument Manager.
5 6 Click OK. The Edit CreateInstance dialog box appears. Click OK. Initialize the Instrument 1 Double-click to add another operation. The Select an Operation dialog box appears. 2 Select Initialize to initialize the simulated Agilent 34401. Click OK. The Edit Initialize dialog box appears. 3 In the Edit Initialize dialog box, GPIB0::23::INSTR has already been entered in the ResourceName field.
4 Click OK. Configure the Instrument 1 Double-click to add another operation. The Select an Operation dialog box appears. 2 Expand the treenode DCVoltage and select Configure. Click OK. The Edit Configure dialog box appears. 3 To set a range of 1.5 volts and resolution of 1 millivolt, enter the following in the Edit Configure dialog box: • 1.5 in the Range field • 0.001 in the Resolution field 4 Click OK. Set the Trigger Delay 1 Double-click to add another operation.
2 Select Close to release all resources associated with the simulated Agilent 34401. Click OK. Display the Reading 1 To display the measurement, from the Main Menu select Display, and click AlphaNumeric. Place the AlphaNumeric object on your workspace. 2 Connect a wire from the return output terminal on To/From myDmm to the input terminal of the AlphaNumeric object. 3 Click F5 or the Right Arrow button on the toolbar to run the program. The Display returns a simulated result.
