All but the simplest of powered equipment needs to be controlled in some way. Even brightness, which can be managed adequately with a single switch, can benefit from additional controls, as then the intensity can be made to stay on for defined periods, switch on and off at planned times, or switch on when one or more sensors are triggered. Traditionally such a control system would have been constructed using relays and timers, but 'smart relays' are a simple, low-cost alternative that offers an additional advantage in that they can be reprogrammed to modify the existing functions or to enable the smart relay to be reused on an entirely different application.
Smart relays have further in common with programmable logic controllers (PLCs) than conventional relays. Yet, the term 'smart relay' is used to differentiate them and emphasize the lower price compared with even the smallest of traditional PLCs. People are processed either appropriating pushbuttons and a small screen on the front panel or via a computer. Smart relays were first started over a decade ago; very soon, there were numerous different models available from suppliers of automation products, and it quickly became apparent that some were rebranded versions of others.
Today there continues a wide choice of smart relays, still with many outcomes being rebranded versions of others. A search of the internet can help to identify which of these are identical and which have minor differences. However, given the step-change in technology that smart relays served when they were first launched, there seems to have been relatively little development since then.
