Relays are an essential part of any electrical system, and consist of an electrical device that normally works by a signal or current activating an electromagnet in one circuit, which then opens or closes another circuit. They provide the electrical isolation and reliable signal switching for all sorts of plant and machinery, including sensitive electronic assemblies such as Programmable Logic Controllers.
Many types of relay are used to ensure a safe and reliable interface between low voltage process peripheral devices, and more advanced level control systems using higher voltages. Many interface relays come with simple plug-in connections using standard or logic sockets, and can be used to switch either AC or DC loads.
Like many other components, relays are modular in design and can be ordered separately, as coupling relays with plug-ins, and can have either solid state or semiconductor outputs. Semiconductor outputs are particularly suitable for solid state systems due to their low power consumption, and some versions have a test button or an LED to show the switching state.
Rowse Automation's catalogue of relays includes Electrically Operated Switches and Plug In Relays in a variety of configuration options, up to the Complete Relay Units. These comprise an 11-Pole industrial relay, plus a relay base unit and mounting bracket or arm. Optional variants can be purchased in 24V AC or DC, 110V and 230V AC, with three or four CO contacts. Additional versions offer plug-in relays with Logical Isolation, so that terminals for the coil and terminals for contacts are isolated on separate levels.