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The industrial relay is still a prominent and necessary feature in the vast majority of control panels and even the threat of digitisation and complimentary technologies cannot replace the core need to switch and control electrical circuits. The industrial relay is one of a few inventions, similar to pen and paper, which technology has tried to replace. But its simple and functional design has made it resilient and more importantly, functionally relevant, even in modern applications.
Daniel Rossek, Regional Marketing Manager at Omron, comments: “Omron has manufactured industrial relays for over 80 years. Despite the core operational principals of the industrial relay not changing significantly since its inception, the development of relay technology to meet the modern needs of industrial applications has not been thwarted." Without doubt the product and market for industrial relays has evolved considerably. Compared to a few decades ago, the use of relays in large logic circuits is now almost redundant. The large “monolithic” control panels, which occupied sizeable real estate on factory floors, have now been replaced by PLCs (software based logic controllers) which provide more functionality in considerably less space than traditional relay logic systems. But, relays still maintained their demand by acting as the interface for these PLC systems, as the control circuit is often based on low voltage (<24VDC) with the requirement to interface with different and higher voltages to control devices like motors or other ancillary equipment.
In reality, miniaturisation has been one of the continual drivers for the evolution of relays, with the market demanding smaller components to eliminate unnecessary space in control panels, as space on manufacturing floors is considered a premium. Relays which once measured several inches now measure just a few millimetres but still maintain the same or improved performance and switching characteristics.
Material science has also played an important part of relay development and the longevity of relays has permitted considerable research into optimising materials used in the construction of relays. Reducing downtime of plant and equipment is increasingly important and whilst the operation of relays is seemingly simple, their failure can result in costly loss of production. Developments in coil materials and construction as well as mechanical components and design have optimised the durability of relays and considerably extended their life expectancy and reliability. Rossek continues: “If you observe a particular type of Omron relay, you may spot a bit of bling! Some Omron relays actually use gold cladding to improve the electrical interface between the contacts, simply because gold offers the best medium for conductance and reliability.”
Another key driver for relay development is the usability aspect; relays are being engineered to design out cost of installation to support their continued usage. The control panel market is a competitive area and the use of relays in terms of the cost to install is an important aspect in the economics of control panel building. Derivatives of relay technology – including multi-relay blocks, premade connection harnesses and interfacing technology like “push-in” – all support the economisation of relay installation.
One thing for certain is that relays have played a critical role in industrial applications for decades. With their ongoing evolution to meet the needs of current and future trends, they will also continue to play a vital role for decades to come.
About the author:
Dan Rossek graduated as an engineer from Kingston University and has been with Omron for fifteen years. He worked as a field application engineer and product manager before moving into marketing. In his dealings with manufacturers, he finds that they are more and more susceptible to the benefits of new technologies and eager to adapt changes to improve performance. Traditionally end users looked two to three years ahead, now clients have a clear idea of where they want to be in ten to twenty years.
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