Industrial Ethernet connectors for high-speed data transfer

Ethernet technology has been established in the office environment for many years. The same technology has been extended into the industrial environment down to field level. Products need to meet the requirements of harsh industrial environments.

The first Ethernet systems were developed in the 1970s. These were company-specific with a rather small range, still far away from a general standard. In the 1980s the first considerations were made regarding a general standard: Ethernet version 1 from 1980 and the ISO/DIS-8802/3 standard from 1985 were important milestones. The 100Mbit/s standard for Fast Ethernet according to IEEE 802.3u from 1995 was a significant step ahead. Today it is the basis for both Ethernet and Fast Ethernet and it is an established standard for office communication.

In factory automation, however, automation systems used fieldbus systems, for example Profibus. Ethernet and fieldbus systems both provided advantages in their applications but they were not sufficiently compatible. For a long time, this prevented a standard communication structure from the office level to the field level. Therefore, transferring the Ethernet standards from the office level into the world of automation (Industrial Ethernet) was a significant step when implementing global communication systems in companies.

High data transfer rates of 100Mbit/s (CAT 5 ISO/IEC 11801 Class D) and a transfer method with no collisions makes Fast Ethernet real-time capable. Management, control and field level are communicating without any perceivable delay, which allows many diverse and interesting applications. Remote maintenance of complete installations and systems via company networks or the internet is now possible.

The harsh industrial environment at device level (sensors and actuators) requires Industrial Ethernet system components to be robust. While IP20 protection (standard RJ45 connectors) is sufficient for components at the office level, the industrial level requires IP65/IP67 protection. Especially important is the high quality of the plug connections because these have to operate reliably despite shock, vibration, humidity, EMC problems, temperature fluctuations and, at times, aggressive media.

D-coded M12 connectors, according to DIN EN 61076-2-101, meet these requirements easily. With 100 mating cycles, IP65/IP67 protection and a shock resistance of 50 'g' it became a standard in Industrial Ethernet. Using Murrelektronik's prewired and moulded M12 connectors prevents wiring errors and is tamper-proof. The d-coded pin design reliably prevents mistakes caused by wrong connections. A 15-degree locking mechanism gives protection against shock and vibration and the 360-degree shielding of Murrelektronik's M12 connectors ensure reliable data transfer even under extreme conditions.

Connectors for dynamic applications

With its Y-coded M12 round plug connectors, Murrelektronik offers another interesting variant for Industrial Ethernet applications. This hybrid option makes it possible to carry power and signals together in a single connector. The metal Y-coding separates the four power contacts from the four signal contacts in the pin design. This makes it possible to transfer 100Mbit/s while at the same time providing two 6A power connections. The installation effort in these applications is reduced, which enables cost savings. To meet all the requirements of the field level, Murrelektronik relies on a PUR cable that is suitable for C-track applications.

Choice of cables

For Industrial Ethernet applications, selecting a suitable cable material is as important as choosing the right connector. For each application, a specially designed cable is available. If the wrong cable type is used, cable failure (for example wire break) can occur in a very short time and the complete installation may fail.

For static applications, the company recommends cost-effective type A cables with a PVC jacket. For flexible applications, type B cables with a PUR jacket is the right choice with an especially good price/performance ratio. For dynamic applications, where cables are exposed to constant torsion or continuously moving drag chains, a highly flexible type C PUR cable is required. In addition, it has to be taken into account that an Ethernet cable that is suitable for C-track applications is not a torsion cable and a torsion Ethernet cable is not suitable for drag chains. It is also very important to pay attention to the minimum bend radius, because using a small radius will destroy the cable.

Murrelektronik offers the right cable for every application. To ensure the maximum lifetime, decisive criteria regarding the application has been defined such as minimum bend radius, degree of torsion, bend cycles and other parameters, and have been confirmed in many tests. Murrelektronik's Industrial Ethernet cables are resistant to external interference, which is ensured by the visual shielding of at least 85 per cent together with the 360-degree shielding concept of the connector. This ensures stable and proper data transfer.

Application-specific protocols

Murrelektronik offers a comprehensive product range for Industrial Ethernet that is complemented by user-specific and customised versions. The right cable is available for all application-specific protocols that were developed on the same physical basis (for example: Profinet, Powerlink, EtherCAT, etc). Shielded M8 connectors have been established for EtherCAT. Sercos III can be recognised by its special red Cat 5e cables, suitable for drag chains. The AIDA work group (Automation Initiative of German Automobile Manufacturers) defined the push-pull power and push-pull data connectors (copper and optical fibre) as standard for Profinet.

Appropriate interface modules such as flange connectors or cable entry systems and the corresponding bus cables are sold by the metre from 100m to 500m (all cables are UL-approved) to complement this product range. All of these cables are suitable for Fast Connect and can easily be pre-wired with the Fast Connect tool.

With experience from many different industries and a comprehensive product range, Murrelektronik is a strong partner for companies that want to create consistent networks based on Industrial Ethernet.

For more information about Industrial Ethernet connectors go to www.murrelektronik.co.uk.