New-Tech Europe Magazine | Dec 2017

Selecting and Implementing M8 and M12 Connectors

Tim Senkbeil, Belden company

How the M8 and M12 Connectors Became the Backbone of Today’s Industrial Automation The year 2015 marks the 30th anniversary of the M12 sealed interconnect system. Over those 30 years, the M12 system has established itself as the go-to option for harsh environments that need reliable, hardened solutions for connectivity. Let’s take a look back at how the connectors were developed, how they evolved, and how it came to be the preferred interconnect system in industrial automation today. The M12, and its smaller cousin, the M8 connector, traces its lineage back to 1982 when a Germany-based company introduced the RK30 – a 7/8 inch circular, 3-pin, screw-type,

“waterproof” connector. This pre- assembled, overmolded connector was rated to IP67, meaning it was dust tight and remained watertight even if temporarily submerged. Used to connect industrial sensors, this precursor to the M12 found its first industrial automation application at an automotive plant, a market that remains key for the M12 connector to this day. Prior to the M12, options were limited: engineers were forced to hard wire or constantly replace connectors that could not withstand harsh environments. Three years later, the M12 connector was introduced and stole the spotlight of the Hanover Fair in 1985. The M12, released with 3- and 4-pin versions, used the smaller metric M12 thread and had a smaller current rating, but retained the IP67 rating.

The 4-pin version allowed for more advanced sensors and actuators to be included in a single system. Little did we know that this product release would set the direction for industrial automation connectivity for the next three decades. The M8 would hit the market four years later in 1989. Following the introduction of the M8, both the M8 and M12 became standardized under IEC 61076- 2-101, which resulted in the two connectors being nearly universally adopted for industrial control systems. Applications for M8 and M12 Interconnect Systems The M8 and M12 have become favorites for anyone in need of

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