Instrument driver

An instrument driver, in the context of test and measurement (T&M) application development, is a set of software routines that simplifies remote instrument control. Instrument drivers are specified by the IVI Foundation^[1] and define an I/O abstraction layer using the virtual instrument software architecture (VISA). The VISA hardware abstraction layer provides an interface-independent communication channel to T&M instruments. The drivers encapsulate the Standard Commands for Programmable Instruments (SCPI) commands, which are an ASCII-based set of commands for reading and writing instrument settings and measurement data. This standard allows an abstract way of using various programming languages to program remote-control applications instead of using SCPI commands. An instrument driver usually has a well-defined API.

The VXIplug&play Systems Alliance was founded in 1993^[2] with the aim of unifying VXI hardware and software to achieve 'plug and play' interoperability for VXI and GPIB instruments. As part of the unifying process, VXIplug&play instrument drivers^[3] were also defined.

When the IVI Foundation took over the Alliance in 2002, it defined a new generation of instrument drivers to replace the VXIplug&play standard. The IVI instrument driver specification intends to overcome the drawbacks of VXIplug&play. These IVI (Interchangeable Virtual Instrumentation) drivers^[4] are currently defined in three different architectures:

1. The IVI-COM driver architecture^[5] is based on the Microsoft Component Object Model.
2. The IVI-C drivers are based on C programming language shared components (shared libraries).
3. The IVI.NET driver architecture was specified in 2010.^[5][6] The IVI.NET drivers are based on the .NET framework.

Instrument drivers allow quicker development of remote-control applications for instrumentation. The drivers reduce the difficulty of string formatting when using SCPI commands by providing a well-defined API. The IVI and VXIplug&play Instrument Drivers use the VISA as the hardware abstraction layer so that hardware-independent applications can be developed.

The VISA library allows test and measurement equipment to be connected through various hardware interfaces. The following interfaces are available:

• Serial Port
• GPIB/IEEE-488
• VXI-11^[7] (over TCP/IP)
• USB488/USBTMC (USB Test & Measurement), USB Test & Measurement Class Specification^[8]
• HiSLIP^[9] (over TCP/IP).

The LAN eXtensions for Instrumentation (LXI) standard defines the communications protocols for controlling test and measurement systems using Ethernet. The standard requires vendors to offer IVI compliant instrument drivers.

• Instrument control
• Standard Commands for Programmable Instruments
• Automation
• IEEE-488
• VISA
• LabVIEW
• LabWindows
• Agilent VEE
• MATLAB
• LAN eXtensions for Instrumentation

• IVI Foundation
• SCPI Consortium Archived 2011-02-06 at the Wayback Machine
• VXIplug&play Systems Alliance Archived 2010-03-29 at the Wayback Machine
• LXI Consortium
• Introduction to Attribute Based Instrument Drivers
• Development Hints and Best Practices for Using Instrument Drivers