PyVISA & Instrument Control with Python

PyVISA is a Python package that enables you to control all kinds of measurement devices independently of the interface (e.g. GPIB, RS232, USB, Ethernet).

As you might know, the programming of test and measurement (T&M) instruments can be real pain. There are many different protocols, sent over many different interfaces and bus systems (e.g. GPIB, RS232, USB, Ethernet).

For every programming language you want to use, you have to find libraries that support both your device and its bus system.

In order to ease this unfortunate situation, the Virtual Instrument Software Architecture (VISA) specification was defined in the middle of the 90's.

VISA is a standard for configuring, programming, and troubleshooting instrumentation systems comprising GPIB, VXI, PXI, Serial, Ethernet, and/or USB interfaces. Today VISA is implemented on all significant operating systems.

Simply put, computers are often used to communicate with measurement equipment to automate a measurement, and there are many ways to implement this communication.

While it is possible to communicate via the serial ports or USB ports using a low-level computer language, it is usually more convenient to use a high level language such as LabVIEW or Python to communicate with instruments. These languages can then also be used to manipulate the data and display it.

Some instruments implement the Virtual Instrument Software Architecture(VISA) which is a standard that gives the instruments plug-and-play capability. 

Programs that understand VISA (like LabVIEW or Python) can recognize which instruments are connected to the computer and communicate with them.

Usually this communication takes place by sending text strings to the instrument. A common format is called Standard Commands for Programmable Instruments (SCPI).

Anyway, some manufacturers do not follow these standards and it is necessary to install drivers to communicate with their instruments.

Note that for instruments that have a microprocessor and memory, it is often possible to upload a program to the instrument and then tell the instrument to execute this program. Popular programming environments for communicating with and controlling instruments are LabVIEW and Python.

Python is a high level programming language that is suitable for small and large projects. It has a large library, operates on many platforms, and is free to download. To communicate with instruments that support the VISA standard it is easy to use the PyVISA package as it allows you to communicate using a variety of interfaces such as GPIB, RS232, USB.

That is it for now. More to come later ⫸

(info source courtesy - https://www.tugraz.at/home)