Reducing the mess of cables in control cabinets begins with fieldbus selection
When designing a new machine or retrofitting a legacy system, cable management is typically an afterthought. It is always possible to bundle wires and add conduit to keep them in place, but ignoring the effect of required cabling until the end increases expenses and equipment footprint. Engineers will likely spend more time wiring a system during commissioning and then tracing wires during troubleshooting, in addition to footing the bill for unnecessary cable length.
Assessing cabling consequences before commissioning provides significant benefits beyond creating better organized enclosures and a cleaner plant floor. Strategic cable management planning in the design phase can produce the 20-20 vision of a cleaner system that reduces cable count and eliminates errors and points of failure. The most effective cable management strategy starts with intelligent component selection. Engineers should implement I/O terminals, fieldbus systems, motion control devices and other machine components that minimize cabling requirements in the application.
It may seem obvious, but it is important to remember that most cabling in factory settings provides either power or networking signals. Although these are not minor tasks, they do not necessitate a tangle of wires stretching across control cabinets to every sensor and drive along the plant floor.
In most cases, the blame for these cable excesses falls on the shortcomings of industrial devices and networks, not the control engineers. For example, traditional Ethernet-based fieldbuses, such as EtherNet/IP or PROFINET, require multiple managed switches, frequently making it impossible to run cables directly from control cabinets to components in the field without using cascading switches or hubs. This requires more hardware to configure the system and introduces additional points of failure. Similar issues arise when supplying machines with power.
The EtherCAT industrial Ethernet system, however, offers complete flexibility in topology without using additional nodes. EtherCAT also integrates a wide range of third-party devices, from drives to I/O and field devices, and enable them all to share data back to the main controller. Gathering data from legacy devices on other protocols without running cables back to the controller is also easy to accomplish over EtherCAT. System-integrated hardware and software gateways can bring data from all manner of fieldbuses and industrial Ethernet systems into the EtherCAT network.
Choosing a fieldbus based on these concerns is the first step, but the network provides the best results when paired with cable-reducing components. One Cable Automation (OCA) via EtherCAT P and pluggable EJ series EtherCAT I/O terminals from Beckhoff are two important pieces.
Want to learn more about the benefits of EtherCAT for limiting cabling? Contact your local Beckhoff sales engineer today.
Sree Swarna Gutta is the I/O Product Manager for Beckhoff Automation LLC.
A version of this article previously appeared in Control Engineering magazine.