411 on M12 Connectors

May 17, 2018 at 8:00 AM

 

Since their introduction in 1985, M12 connectors have grown to become the go-to interconnect system for industrial automation. These rugged connectors provide reliable connections in the harshest environments and have revolutionized the world of industrial automation connectivity.

 

M12 connectors are circular connectors that have a 12-mm locking thread and often boast IP ratings for protection against liquids and solids. They are ideal for connecting sensors, actuators, as well as industrial Ethernet and Fieldbus devices, mostly in industrial automation applications and in corrosive environments.

 

Prior to the inception of the M12 connector, engineers had to hard wire or repeatedly replace connectors that couldn’t endure in harsh conditions. Initially released with 3 and 4-pin models, the original M12 connector had a smaller current than its predecessor, the RK30, but still provided the protection of an IP67 rating. The 4-pin M12 connector allowed a single system to include more advanced sensors and actuators. Today, these rugged connectors are available with 3, 4, 5, 8 and 12-pin configurations with additional locking styles continuously being developed, such as bayonet and push-pull.

 

In addition to factory automation, M12 connectors and M12 cable assemblies are used in measurement and control, communications, transportation, robotics, agriculture and alternative energy applications. Choosing the correct pin count depends on the specific application. Three and 4-pin models are needed for sensors and in power applications. Ethernet and PROFINET require 4 and 8 pins. DeviceNet and CANbus mostly use 4 and 5-pin connectors. Twelve-pin models are typically specified for various signal applications.

 

Along with different pin counts, M12 connectors have multiple styles of key coding to prevent improper mating.  Here are the most common coding types and what they’re used for:

 

·       A-coded: sensors, DC power and 1 Gigabit Ethernet

·       B-coded: PROFIBUS

·       C-coded: AC power

·       D-coded: 100 Mbit Ethernet

·       X-coded: 10 Gigabit Ethernet

·       S-coded: AC power (will be replacing C-coded power parts)

·       T-coded: DC power (will be replacing A-coded power parts)

 

The most popular types of M12 coding are A, B, D and X.  The A, B and D-coded connectors are some of the first M12 connectors and have been on the market the longest. X-coded connectors are rising in demand for high-speed industrial Ethernet and will ultimately take the place of A and D-coded parts in Ethernet applications. The newest code designs being developed are K-coded for AC power and L-coded for PROFINET DC power.

 

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