The advance of Ethernet into industrial applications is a development that cannot be ignored. The allure and promise of Industrial Ethernet is that it will enable complete integration of machines and systems into a single network capable of supporting the execution of a variety of system functions.

The core parts needed to build such a system capable of delivering on this promise include a standard Ethernet I/O system that offers IP20 and IP67 protection with integrated wireless technology. Because of the increasing complexity of machines and systems, and the harsh demands for environmental protection, the selection of an I/O system requires careful consideration.

Flexibility in the control cabinet
Most I/O functions are covered by devices of protection class IP20, which is suitable for installations in a control cabinet or terminal box. A modular IP20 I/O system can be assembled to provide all necessary functions and it can be expanded as required. Assembling such a system is simple, select an appropriate network bus coupler and then connect it to the system modules required for the application.

System modularity allows for both custom configurations and subsequent expansion. For Industrial Ethernet, bus couplers are available for Modbus/TCP, Profinet or Ethernet/IP protocols. The physical network connection is achieved using RJ45 plug connectors.

Some bus couplers include a built-in switch, which offers a notable advantage: it eliminates the need for additional Ethernet infrastructure components when linking different I/O stations. A line structure topology, quite popular in older fieldbus implementations, can be set up quickly and easily, creating savings in both material costs and installation time.

Beyond form factors and mounting differences, a modular IP67 I/O system is essentially the same as an IP20 I/O system: a collection of Ethernet networked stations, with each station consisting of an Ethernet bus coupler supporting a local bus linked to corresponding I/O devices. Diagnostic information, such as short-circuit or overload, is forwarded to the Ethernet network through the bus coupler. This configuration enables a pinpoint diagnosis of the I/O system and significantly helps to reduce downtime.

To minimize installation times for start-up and maintenance, quick-locking M12 round-plug connectors connect sensors and actuators. For applications with serious space limitations, you can choose I/O devices with M8 connectors. With a width of less than 30 mm, they can be mounted to standard sections without unwanted protrusion. If an application near an IP20 station also requires several IP67 I/O devices, a special branch terminal connects both M12 and narrow M8 devices. This eliminates the need for an additional Ethernet bus coupler for the IP67 devices by allowing devices to be integrated into the local bus of the IP20 bus coupler.

Wireless I/O systems allow temporary or mobile installations to be integrated into an I/O system. They offer an alternative to critical connections previously dependent on slip rings and drag chains.

Wireless I/O devices are available in both IP20 and IP67 protection categories. Many use the Bluetooth wireless standard to transmit digital and analog signals to a wireless base station, which is connected to the local bus of an Ethernet bus coupler. Transmission data include process data as well as diagnostic information about the I/O device and the quality and condition of the wireless connection. All diagnostic data is also made available through the bus coupler located in the Ethernet network.

Interplay simplifies project planning
Many applications require I/O devices in both IP20 and IP67 protection categories. Integrated wireless functions can prove highly advantageous on moving or hard-to-access system parts. The most critical aspect to consider is that these different systems, each with special functions and features, must work together for a seamless solution. This can be achieved by regulating their behavior in terms of installation, project planning and programming. The creation or expansion of machines and systems can be simplified by implementing a comprehensive network that extends from the control cabinet to the field and all the way to wireless functions. As a result, it is no longer necessary to control and administer different systems, saving training time and providing a uniform system behavior that facilitates maintenance and repair work.