Test Instrument Drivers Tutorial
- details of the technology and methodologies use for test instrument drivers, what they are and how they are used.
Test instrument drivers are used in many computer controlled test systems.
These instrument drivers are used within environments such as PXI, VXI and many other automated test systems including those controlled by GPIB, Ethernet or even LXI.
Test instrument drivers provide an easy and effective method of driving as they are often able to provide a much easier interface for the programmer to use. They may take away the need for programming at machine or higher levels, making the control much easier.
Instrument driver basics
An instrument driver consists of software that is used by the system to enable control and access of data from a given instrument. The driver is specific to a particular test instrument, or sometimes an instrument type.
The instrument drivers allow programming of operations within the test instrument like configuring an operation, reading data from the test instrument, writing data to it, or triggering it.
Instrument drivers allow the set-up, operation and reading of data from a test instrument that is controlled by a computer to be controlled in a simple standard method. This considerably simplifies the operation and reduces reduce test program development time by eliminating the need to learn the programming protocol for each instrument. In some cases, programming an instrument could virtually mean writing to and reading from registers, making the programming virtually like writing machine code.
Industry driver standards
One of the key advantages of test instrument drivers is their ability to be used across a variety of platforms and technologies. This means that the development of industry standards is key to their success.
There are a number of driver standards that are in common use:
- VISA drivers: VISA stands for Virtual Instrument Software Architecture, and it was originally designed for VXI systems. However VISA has also been adopted for use in many other systems including PXI and many other forms of test system.
VISA enables interoperability by providing a method of developing instrument drivers with a common approach. This has the advantage that it makes using instruments of modules from different manufacturers within a system far easier. Read more about the VISA instrument drivers.
- IVI drivers: The abbreviation IVI stands for Interchangeable Virtual Instruments. IVI is a driver standard for virtual instrumentation which is supported by the IVI Foundation.
IVI builds on top of VISA and the aim is that it provides some interchangeability between instruments without the need for software reprogramming, if, for example there is a need to change from one instrument to another of the same class or type, e.g. if a change between two DC power supply types is required. Read more about the IVI instrument drivers.
Most test equipment manufacturers realise the importance of test instrument drivers, and most of them will develop instrument drivers for their equipment. Where the instrument driver is specific for an industry management system such as LabVIEW, etc, the manufacturers will development for thee platforms.
By providing these drivers, the manufacturers will encourage use of their equipment.
By Ian Poole
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