{"id":8386,"date":"2026-06-09T16:49:09","date_gmt":"2026-06-09T16:49:09","guid":{"rendered":"https:\/\/www.yunrui-controls.com\/?p=8386"},"modified":"2026-06-09T17:01:36","modified_gmt":"2026-06-09T17:01:36","slug":"4-20ma-signal-industrial-automation","status":"publish","type":"post","link":"https:\/\/www.yunrui-controls.com\/ko\/4-20ma-signal-industrial-automation\/","title":{"rendered":"Why 4-20mA is the Universal Language of Industrial Automation"},"content":{"rendered":"
\n
\n
Technical Guide<\/div>\n

Why 4-20mA is the “Universal Language” of Industrial Automation<\/span><\/h1>\n

Understanding the Engineering Principles Behind the World’s Most Widely Used Process Control Signal<\/p>\n

\n
\n
4-20mA<\/div>\n
Current Loop Standard<\/div>\n<\/div>\n
\n
2-Wire<\/div>\n
Power & Signal<\/div>\n<\/div>\n
\n
24VDC<\/div>\n
Standard Supply<\/div>\n<\/div>\n
\n
HART<\/div>\n
Digital Overlay<\/div>\n<\/div>\n<\/div>\n<\/div>\n
\n

Introduction: The Industry Standard<\/h2>\n

If you ask what is the most classic and widely used signal in industrial automation, the answer is undoubtedly the 4-20mA current signal<\/strong>. From oil refinery units in petrochemical plants to fermentation tanks in pharmaceutical facilities, from water level control in wastewater treatment to temperature regulation in power plants, the 4-20mA signal is everywhere.<\/p>\n

It is known as the “universal language” of industrial automation\u2014much like English in international communication. But why exactly 4-20mA? Why not 0-10V? Why not 0-20mA? The answer lies in profound technical principles and engineering wisdom developed over decades.<\/p>\n

Part 1: What is the 4-20mA Signal?<\/h2>\n

1.1 Basic Concept<\/h3>\n

4-20mA (4-20 milliamperes)<\/strong> is an analog current signal standard where:<\/p>\n

\n