It used to be only high-end test equipment that had some sort of remote control port. These days, though, they are quite common. Historically, test gear used IEEE-488 (also known as GPIB or, from the originator, HPIB). But today, your device will likely talk over a USB port, a serial port, or a LAN connection. You’d think that every instrument had unique quirks, and controlling it would be nothing like controlling another piece of gear, especially one from another company. That would be half right. Each vendor and even model indeed has its unique command language. There has been a significant effort to standardize some aspects of test instrument control, and you can quickly write code to control things on any platform using many different programming languages. In a few posts, I will show you just how easy it can be.
The key is to use VISA. This protocol is defined by the IVI Foundation that lets you talk to instruments regardless of how they communicate. You do have to build an address that tells the VISA library how to find your device. For example: “TCPIP::192.168.1.92::INSTR.” But once you have that, it is easy to talk to any instrument anywhere.
I say that thinking it is a problem is half right because talking to the box is one task of the two you need to complete. The other is what to say to the box and what it will say back to you. There are a few standards in this area, but this is where you get into problems. Continue reading “How To Talk To Your Scope”
In this article, let’s figure out places where you can use a logic analyzer, and places where you can’t. We’ll start with the first limitation of logic analyzers – capture speed. For instance, here’s a cool thing you can buy on Aliexpress – a wristband from TTGO that looks like a usual fitness tracker, but has an ESP32 in it, together with an IMU, an RTC, and an IPS screen! The seller also has an FFC-connectable devboard for programming this wristband over UART, plus vibromotor and heartrate sensor expansion modules.
