The industrial control chassis on the market is generally a 19-inch standard rack, and the 4u industrial control chassis is the most common.

 

The specified dimensions are wide (482MM = 19 inches) and high (multiples of 44.5MM).

 

Since the width is 19 inches, the rack that satisfies this requirement is sometimes referred to as a "19-inch rack."

 

The thickness is 44.5 MM as the basic unit. 1U is 44.5MMcm, 2U is 2 times 2U is 89MM. In other words, the so-called "1U industrial computer" is a product that meets the EIA specifications and has a thickness of 44.5 MM. Products designed to fit into a 19-inch rack are generally referred to as rack servers.