Agilent Technologies E6432A manual Introduction, Programming Environments, VXI Interfacing

Introduction

Today’s VXI instruments communicate with application programs through plug&play drivers. In some cases, these drivers are just one way to communicate. For the E6432A microwave synthesizer, its plug&play driver is the only means of communi- cation with the host controller or its application programs.

This product note provides an overview of the communication process, the range of hardware and software configurations supported, and an introduction to the features of the instrument made available through the plug&play driver.

The E6432A microwave synthesizer is a register-based device, rather than a message-based device. There are two reasons for this. First, the E6432A is designed to be a system source rather than a bench source, so its user interface and command set are simple and straightforward. A register-based design supports this application. Secondly, the E6432A employs a fast-switching architecture in both frequency and amplitude switching. Switching times of less than 400 µs can be achieved in real customer applications only if the E6432A processing time is kept to well under 50 µs. This can only be accomplished with a register-based design.

Most modern automated test systems use programming environments and VXI interfaces that support the plug&play driver architecture. These systems will easily integrate the E6432A. For systems using older, legacy software and VXI interfaces, support for the E6432A may require rewriting and/or changing interfaces. These conditions will be covered in this note.

Programming Environments

To support the E6432A plug&play driver, the operating system founda- tion required by the host controller is Microsoft Windows NT® 4.0, with Service Pack 3 or above installed. Other operating systems, such as Windows 95/98, UNIX®, or MacOS are not supported at introduction.

Application programs running on Windows NT that are compatible with the E6432A plug&play driver are:

●HP VEE 4.0 or higher

●National Instruments LabView and LabWindows/CVI versions 4.0

or higher

●Microsoft Visual Basic version 5.0 or higher

●Microsoft Visual C/C++ versions 5.0 or higher

Application programs such as Agilent Basic for Windows have no provision for communicating with plug&play drivers and are therefore not supported.

VXI Interfacing

There are several interfacing choices available from host controller to VXI instruments. Three of these are sup- ported by the E6432A plug&play driver. They are:

●VXI Embedded Control (for exam- ple, E6234A running Windows NT)

●National Instruments VXI-MXI-2

●IEEE-1394 ("Firewire") (for example, E8491A)

The remaining VXI interfaces (HP and National Instruments GPIB-VXI, and National Instruments MXI-1) are unsupported.

The VXI data specification for the E6432A is A16/A24, D16/D32. Due to the large size of frequency registers, floating point arithmetic is a must. The interface must be capable of allocating a large block size of A24 address space (256k). GPIB inter- faces are unsupported because they are fundamentally message-based interfaces. They are not designed to communicate with register-based instruments without special, propri- etary software that must be written and downloaded into their memories prior to using the plug&play driver.

Microsoft, Windows and Windows NT are U.S. registered trademarks of Microsoft Corporation.

UNIX is a registered trademark of the Open Group.

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