June 2019

74 n CONNECTORS M12: the ‘workhorse’ of connectors A lthough the use of wireless connection technologies is increasing from the shop floor to the top floor, physically connecting plant, machinery and controllers demands connectors that will provide reliable power, signal and data connections. The connectors need to withstand“hazards” found in the production arena such as vibration, water and dust. They also need to be able to transmit the higher data rates being used increasingly in automated production. The most common connector in production environments is the multi-pin circular connector developed in the 1930s for use in airplanes and refined since then to cope with, among other things, dirty environments, high- pressure washing and extremely fast data rates. Today, the most popular circular connector in production environments is the M12 system. It is used widely to connect sensors and actuators as well as applications such as fieldbus and industrial Ethernet. Screw locking thread connectors are ideal for ensuring reliable connections in environments where it is vital to protect against dust, water and other contaminants. The 12mm locking thread M12 can be specified with protection levels up to IP69k, making it suitable for applications where jet washing occurs. Development of the M12 connector as we know it today began in 1982 when a German car-maker wanted to minimise downtime by making sensors“connectable”on its production lines. The next development followed the need for field-attachable connectors. This is when binder entered the market with the first four- pole M12 connectors with screw terminal closures, thus laying claim to having invented the field-attachable M12 connector. During the 1990s, around 80% of sensors used in manufacturing were hard-wired, with the other 20% being connected. Today, only 10% are hard-wired with a massive 90% being connected. M12 connectors are available in cable-moulded or field-attachable versions. Since the introduction of three- and four-pin versions of the M12, manufacturers have developed a huge variety of models and options. M12 connectors are available with 3, 4, 5, 8 and 12 pins, depending on the application. For example, Profinet and Ethernet need 4 and 8 pins, while most sensor and power applications use 3 and 4 pins. Signal applications can require up to 12 pins, while communications protocols such as fieldbuses and DeviceNet normally need 4 or 5 pins. The connectors are available in straight or right- angle versions. As well as IP67, M12 connectors are available with IP65, IP68 and IP69K protection ratings. This allows them to be used in demanding applications, subject to high- pressure jet washing. Corrosion resistance is achieved by using stainless-steel nuts. Eight-pole, X-coded connectors can achieve data transmission speeds of up to 10Gbit/s. This is done by isolating the four pairs of wires from each other with a cross or X-coding shield for separation of the transmissions. The X-coding conforms to the industry standard IEC 61076-2-109 and is specified for broadband transmission by Ethernet protocols, including Profinet. Decoding the codes The sheer variety of M12 connectors can make selection difficult – a process made harder by the codes used to denote the suitability of connectors for an application. IEC 61076-2-101 describes the relevant coding/application combinations. The list below shows the application that each coded M12 connector is suitable for. These codes help to avoid connector mismatching, and to ensure proper connections for each application. Over the years, the versatility of the M12 connector has grown, not only with new pin counts, but also the availability of pre-wired connector assemblies, shielded versions to cope with higher data rates, and several methods of termination including crimp, screw, solder and wire clamp. Circular M12 connectors can be integrated into equipment or mounted on PCBs. Today’s M12 connectors can handle a wide variety of cable types and sizes, increasing their range of applications even further. The M12 connector is the go-to technology for applications that need robust, reliable power, signal and data connections in demanding applications. As new variants keep coming, it will remain the“workhorse”of the industry for years to come. n M12 connectors – often called the interconnection “workhorse” of the automation sector – come with many different pin counts and codings. It is important to select the right connector for the application. Binder’s David Phillips offers advice to help you make the right choice. Code Application A Power, signal, CAN, CANopen, DeviceNet (to IP69k) B Profibus (IP67/IP68) D Ethernet, EtherCat, Profinet, Sercos (IP67) X High-speed Ethernet, Profinet (IP67) S AC Power (IP67) T DC Power (IP67) K DC Power (IP67) L AC Power (IP67) These A-coded M12 connectors have been designed specifically for food and beverage applications, in accordance with FDA 21 CFR. These are also suitable for other uses with stringent hygiene requirements, such as in the pharmaceutical and chemical industries. They provide protection to IP68 and IP69K, and can therefore resist high- pressure cleaning with aggressive chemicals. June 2019 www.drivesncontrols.com