Agilent Technologies

Agilent 34401A 6-1/2 Digit Multimeter VXIplug&play Instrument Driver Read Me

README.TXT for Agilent 34401A Digital Multimeter
Driver Revision A.02.16
July 5, 2005


1 Introduction

2 VTL/VISA Specific Information
2.1 Instrument Addresses
2.2 Using Callbacks and Soft Front Panel Timeouts
2.3 Read Status Byte

3 Using the 34401A Driver in Application Development Environments
3.1 Microsoft Visual C/C++
3.2 Borland C/C++
3.3 Microsoft Visual Basic
3.4 Agilent/HP VEE
3.5 LabWindows/CVI

4.0 Known Defects

5.0 Online Information

6.0 Revision History

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1. Introduction

The help file included with the 34401A driver contains
instrument and programming information. This readme file contains
additional information for the VXIplug&play programmer.

The 34401A Windows 95 and Windows NT drivers are actually a single 32-bit

This 34401A driver conforms to all portions of the VXIplug&play driver
standard which are applicable to conventional GPIB and other non-VXI
instruments (that is, rack and stack instruments). The formal VXIplug&play
standard only covers VXI Instruments, and two elements of the standard do not
apply to the 34401A since it is not a VXI instrument. First, there is no soft
front panel, as the 34401A can be controlled from it's hardware front panel.
Second, there is no knowledge base file, which is primarily a physical
description of a VXI board.

Aside from these exceptions, you'll find the same features in this driver as
in Agilent's other VXIplug&play drivers.

1. Conformance with the VXIplug&play standard. The only exceptions are that
it does not have a soft front panel or a knowledge base file.

2. It is built on top of, and uses the services provided by VISA. VISA
supports GPIB and VXI protocols. The driver can be used with any
GPIB card for which the manufacturer has provided a VISA DLL.

3. It includes a "Function Panel" (.fp) file which allows it to be used
with visual programming environments such as Agilent VEE, LabWindows,
and LabVIEW.

4. It includes a comprehensive on-line help file which complements the
instrument manual. The help file presents application programming
examples, a cross-reference between instrument commands and driver
functions, and detailed documentation of each function, with examples.

5. Source is included so that the driver can be modified if desired. The
source conforms to VXI Plug & Play standards. Modifications should only
be done by people who are familiar with the VXIplug&play standard.

6. It includes a Visual Basic include file (.bas) which contains the function
calls in Visual Basic syntax, so that driver functions can be called from
Visual Basic. If you use Visual Basic with this driver, you should be
familiar with C/C++ function declarations. In particular, care must be
taken when working with C/C++ pointers.

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2. VISA Specific Information

The following topics refer to instances when the driver is used with
different versions of VISA.

2.1 Instrument Addresses

When using VXIplug&play instrument drivers, instrument addresses must
be all uppercase letters. Implementation of the addressing scheme is
vendor specific and some vendors support mixed cases. However, for
maximum portability, the instrument address should use uppercase
characters only.

For example: use "GPIB0::20" instead of "gpib0::20"

2.2 Using Callbacks

Callbacks are not supported with this driver.

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3. Using the 34401A Driver in Application Development Environments

This section offers suggestions on using the hp34401_32.dll within
various application development environments.

3.1 Microsoft Visual C++ 4.0 (& higher) and Borland C++ 4.5 (& higher)

Refer to your Microsoft Visual C++ or Borland C++ manuals for information
on linking and calling .DLLs.

A.) The driver uses Pascal calling conventions.

B.) Rebuilding the driver DLL should be done in a different directory
than the one the driver was installed in order to differentiate the changes.

3.2 Microsoft Visual Basic 4.0 (& higher)

Refer to the Microsoft Visual BASIC manual for information on calling DLLs.
The BASIC include file is hp34401.bas, which is contained in the directory
~\win95\include or ~\winnt\include. The ~ refers to the directory in the
VXIPNP variable. By default this is set to C:\VXIPNP or C:\Program Files\VISA,
depending on what version of VISA you are using. You may also need to
include the visa.bas file that comes with your VISA DLL.

3.3 Agilent/HP VEE 3.2 (& higher)

Your copy of Agilent VEE for WINDOWS contains a document titled "Using
VXIplug&play Drivers with VEE for Windows." This document contains
the detailed information you need for VEE applications.

3.5 LabWindows CVI/(R) 4.0 (& higher)

The 34401A driver is supplied as both a source code file and as a dynamic
link library file (dll). There are several advantages to using the dll
form of the driver. These include:

1. Transportability across different computer platforms

2. A higher level of support from Agilent Technologies for the compiled driver

3. Faster load time for your project

Labwindows/CVI (R) by default will attempt to load the source version
of the instrument driver. To load the dll you must include the file
hp34401.fp in your project. This file can be found in the ~\win95\hp34401
or ~\winnt\hp34401 directory. DO NOT INCLUDE hp34401.c in your project.
You must also provide an include path for hp34401.h. This is done by
adding the directory ~\win95\include or ~\winnt\include to the include
paths (CVI Project Option menu) if you have not already done so. The ~
refers to the directory in the VXIPNP variable. By default this is set
to C:\VXIPNP or C:\Program Files\VISA, depending on what version of
VISA you are using.

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4.0 Known Defects

There are no known defects in the 34401A driver.

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5.0 Online Information

The latest copy of this driver and other Agilent VXIplug&play drivers can
be obtained via the Web at URL:

The 34401A driver is located in a self-extracting archive file called

If you do not have Internet access, the drivers can be obtained by
contacting your country support organization. In the US, the phone
number is 800-452-4844. A list of contact information for other
countries is available at:

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6.0 Revision History

A.02.00 November 19, 1996 Initial Release.
A.02.10 March 10, 1996 Second Release.
A.02.11 July 8, 2002 Third Release.
Agilent rebranding. Updates to help and .fp files. Added missing
functions to .bas file.
A.02.12 December 6, 2002 Fourth Release.
Added pass-through functions.
A.02.14 April 2, 2003 Fifth Release.
Added #ifdef INSTR_CALLBACKS to .h file for VEE, Agilent Toolkit
Added hp34401_readStatusByte_Q to help and .fp files
hp34401_calcAverCoun_Q misspelled in .fp file
hp34401_opc_Q had wrong number of parameters in help and .fp files
A.02.15 June 17, 2005 Sixth Release.
hp34401_func_Q failed on some functions
A.02.16 July 5, 2005 Seventh Release.
hp34401_configure & hp34401_configureDefault failed on CURR:DC

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