Stephen Hayes, managing director at Beckhoff Automation UK, explores how modern automation can help significantly reduce electrical complexity.
For all the uncertainties and instabilities that the industrial sector has faced in recent years, one thing has remained constant: automation, and investment in it, has grown steadily. These systems provide a wealth of benefits for industrial businesses, but they can present a series of challenges for electrical engineers in terms of wiring and control cabinet functionality. However, things may be set to change.
Automation has been a consistent priority for industrial business leaders for much of the past decade. Findings from BDO’s 2019 ‘New Economy: Investing in Automation’ report highlighted that 87% of surveyed UK businesses had invested in automating a key process in the previous 12 months. In addition, 21% of chief financial officers identified automation as their most important investment for the coming years.
Then there is the 2020 annual manufacturing report, which reported that 63% of businesses have already actively adopted automation and robotics. Together, these surveys paint a clear picture of an industry already reasonably automated, with further automation investments on the horizon.
It is not difficult to see why this is the case. Automation allows for efficient completion of repetitive, monotonous tasks such as the handling of materials or packing of products, and similarly can manage processes with a lower rate of error than human workers, such as quality inspection. It supports human workers to complete other tasks while the automated systems operate, which allows for greater throughput, output and overall productivity. As more systems can interconnect and share data, these gains become even more substantial.
However, adopting increased levels of automation is not without its challenges. There are, first and foremost, the practical issues of adding a new automated machine to an existing production line. A plant requires ample space to support the machine, and plant managers will also need to account for the planned downtime on a production line while the system is integrated and set up.
Of course, automated systems can quickly recuperate productivity losses if set up properly, but then there is the matter of how much downtime is required per installation. As electrical engineers will likely know well, much of this downtime comes from connecting automated machines safely into control cabinets.
Electrical issues
Unfortunately, as automation systems become more advanced, they require more space in control cabinets to house power and communication cabling. This contributes to control cabinets starting to occupy large footprints, which reduces the space available for plant managers. These densely populated plants also present issues for electrical engineers.
The typical control cabinet contains a combination of higher voltage — often around 480V — power supply cables, 24–120V control wiring and, increasingly, communications cabling. The conductor for each cable and wire needs to be sufficiently separated to prevent signal disruption and the proliferation of electromagnetic interference (EMI).
Generally, magnetic fields are generated as current passes through the conductor. This field will periodically change direction as the alternating current (AC) flow changes, which can induce an erroneous voltage in other control wiring in close proximity. This EMI induced voltage can produce a false signal for connected equipment or distort supplied voltage, leading to erratic equipment behaviour, compromised performance and accelerated component failure. Part of the management of this issue involves ensuring that cables are sufficiently shielded and separated, which inadvertently increases the required footprint of the control cabinet.
Then there is the fact that with an ever-increasing amount of wiring comes more opportunity for wiring errors. These errors elongate the installation downtime of adopting a new automation system, while also making future manoeuvring of the machine more complex.
Modern automated systems possess a great deal of components that require wiring through a cabinet, with each cable and wire introducing another instance of EMI risk. This presents a possibility of more complex automation systems producing a greater deal of problems for electrical engineers.
In Beckhoff’s view, this is not a sustainable approach to automation. When we consider the limitations presented by control cabinets in terms of footprint, electrical reliability and installation complexity, it’s clear that an alternative is needed. Fortunately, new automation technologies are moving away from the conventional control cabinets, with the support of a new approach to cabling.
Shrinking cabinets
For automation components and systems, there are two key cabling requirements: power and control. A distributed servo drive, for example, needs power to operate but also must be able to communicate data to allow for motion control. The obvious solution is to find a way of integrating power and communications into a single cable to immediately halve the number of trailing cables and wiring errors. However, finding an effective way of doing this has been far from obvious.
Hybrid cabling is not a new concept, but it is one that has faced difficulties of execution, especially in terms of compatibility with multiple systems. This is why we have seen the development of a new type of cable in the form of EtherCAT P, which combines the 24V DC power supply required by many systems in a single four-wire standard Ethernet cable. The system and sensor supply voltage and the peripheral voltage for actuators are electrically isolated from each other and can supply up to three A of current to connected components.
This innovation alone streamlines the number of cables, which immediately theoretically halves the size of control cabinets. However, it’s when we couple it with distribution and power supply modules for machine components that we start to see the scale of the impact. Using a power distribution module compatible with EtherCAT P in a machine with multiple servo drives, for example, allows up to five servo systems to operate from a single module with only the module requiring control cabinet connection.
What this means is a plant could invest in an automation system with five servo systems to control various motion processes, with only a single wire needing to run to the control cabinet. Immediately, the risk of wiring errors is substantially reduced, and the installation complexity faced by electrical engineers is mostly eliminated. This allows electrical engineers to complete automation integration and wiring tasks much more efficiently. It then also means the control cabinet can be much smaller, occupying less space on a factory floor and leaving more room for productive investments.
This is all made possible by new automation technologies, which have supported a move away from the bulky control cabinets that have long been a staple of factories and production lines. As more automation systems are adopted into industrial environments and investment continues to grow, we can avoid creating more difficulties for electrical engineers. Instead, we can all reap the benefits of automation, without cabinets.
