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A 4-20 mA analog output is a universally recognized industry standard for relaying electrical signals (as currents) over long distances. For example, many sensing instruments such as pressure transmitters and transducers use a 4-20 mA output as a simple and reliable method to convey information from the field to a system control room. If you want to learn more about this type of output, and the benefits of the 2-wire connection option vs. a 3-wire option, you've come to the right place. I have been a product leader at Ashcroft for almost two decades and have extensive experience in pressure and temperature measurement. During that time, I've been asked a lot of questions about how things work and the benefits of selecting one measurement device over another. We created our Understanding the Basics series to give those who are new to the industry a framework of information to use as a valuable point of reference when needed. In this article, you will learn about 4-20 mA analog outputs, including where they are used, how they work, and the advantages and challenges of using the 2-wire vs. a 3-wire in your application. When you're finished, you'll know if this type of output is right for you.

This article was originally published on June 27, 2022, and was updated on March 20, 2024. Critical process applications demand implementing critical safety measures. The safety of your operators and your customers depends on using high-quality pressure measuring instruments that can help you avoid disaster. The one thing I've learned in over 25 years of industry experience is that you can never be too careful. Unfortunately, when I visit process plants and other facilities, I often find that proper instrumentation is not installed on many applications. Understanding which instruments to use can be the difference between a successful operation and a dangerous one. In this article, you will learn why installing both an analog pressure gauge and a pressure transmitter to monitor air, gas or liquid pressure in challenging industrial applications is a good safety strategy. They each have a specific job to do. When you are finished reading, you can decide if having both types of instruments working for you is the right decision. You will also get links to additional information that you may find useful.

A pressure transducer, which can also be referred to as a pressure transmitter or pressure sensor, is an electronic device that measures and monitors the air, gas or liquid pressure flowing through industrial systems. Although they appear small, these instruments are built with advanced technology to provide accurate and reliable pressure measurements at different stages of the process. Ashcroft is an industry leader in pressure measurement instrumentation and created this article to provide a basic foundation of information about transducers for the industry novice. Read on to learn how they work and where they are used. You will also get a high-level overview of the different types of sensors, manufacturing standards, sensor accuracy and more. When you are done reading, you will also find additional resources about transducers that may interest you.

For the industry novice looking to understand the basics of pressure measurement instruments, it can be confusing and overwhelming to search through the seemingly limitless number of available transmitters and transducers.

When you’re working in pharmaceutical or biotech applications, whether it’s an HVAC system or an isolation or clean room, it’s vital to maintain clean, contaminant-free environments. If you don’t, you risk the safety of others and the possible contamination of your processes. You need a pressure transmitter that can reliably monitor ultra-low pressure, but the number of products available on the market can be overwhelming.