VTI Instruments EMX-4016B, Руководство пользователя

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APPENDIX B 33
I
NSTRUMENT
D
RIVERS
O
VERVIEW
Three drivers, VTEXDigitizer, VTEXDSA, and VTEXPlatform (or libDigitizer, libDSA, and
libPlatform, respectively, for Linux), are used to program the EMX-4250/4350/4380 instruments.
The “Digitizer” drivers are common drivers used by all EMX digitizer cards provided by
VTI Instruments. For a simple data acquisition application, the “Digitizer” driver may be the only
driver the user needs to use. The “DSA” drivers are essentially a super set of digitizer driver. In
addition to the data acquisition functionalities in “Digitizer” driver, the “DSA” driver also supports
the EMX-1434’s signal output and tachometer input capabilities. The one feature available in
“Digitizer” driver, but not in the “DSA” driver is support for IVI class compliant interfaces. In
general, it is recommended to use the “DSA” driver instead of “Digitizer” driver unless the user
needs to use the IviDigitizer or IviScope class compliant interfaces for instrument
interchangeability. The “Platform” drivers are used to configure the EMX-2500 Ethernet controller
card and the CMX09/18 PXIe chassis. Using the EMX-2500 in an CMX chassis makes
EMX-4250/4350/4380-based data acquisition systems LXI devices so that they can synchronized
using IEEE 1588 PTP and LAN events over Ethernet (see Figure 4-6).
IVI D
RIVERS
The IVI Foundation defines IVI driver specifications. IVI specification information is available at
the IVI Foundation website,
www.ivifoundation.org . The IVI-3.2 Inherent Capability Specification
defines a common set of basic functionality that all IVI driver must support. This ensures that users
can perform basic operations and identify its capability for any IVI driver using the exact same API
functions. The IVI drivers are implemented using a common code provided by the IVI Foundation
in order to guarantee this consistent behavior. This common code is called IVI Shared Components.
The IVI Shared Components must be installed separately prior to any IVI drivers from VTI. The
shared components installer is available for download from the IVI Foundation website.
The IVI Foundation specifies that the IVI driver be based on Microsoft Component Object Model,
called IVI-COM and an IVI driver using standard C language API, called IVI-C. For those who
develop applications in Windows .NET languages, such as C#, VB.NET, or other Object Oriented
Language, such as C++, IVI-COM gives APIs logically organized by interfaces. IVI-C gives more
traditional C language functions.
While VTI’s IVI drivers are architected based on IVI-COM, the driver installer also installs a
wrapper library that exposes IVI-C functions so that the user can use develop in both types of
environment.
Header and Library Files
The IVI driver specification defines the install directory structure and software components to be
installed. For 32-bit Windows systems, the root of install directory is C:\Program Files\IVI
Foundation\IVI. For 64-bit Windows systems, the 32-bit driver is installed at C:\Program Files
(x86)\IVI Foundation\IVI and the 64-bit driver is installed at C:\Program Files\IVI Foundation\IVI.
Driver header files and library files are installed in several sub directories. The
Bin subdirectory
contains IVI-COM and IVI-C driver DLL files. The Component subdirectory contains IVI-COM
and IVI-C shared components files. The Drivers subdirectory contains the driver specific sub
directories. VTEXDigitizer, and VTEXDSA driver’s online help files and example programs are
installed here. The
Include subdirectory contains header files. The Lib subdirectory contains 32-bit
import library files. The Lib_x64 subdirectory contains 64-bit import library files.