Relays have been the traditional building blocks of control since the 1950s. Still in wide use for simple control or power conversion, styles include electro-mechanical general or special purpose relays such as high power or hazardous location styles, as well as solid-state relays.
Electromechanical relay switches are available in square relay / ice cube relay, plug-in relay, octal relay, power relay, hazardous location (HAZLOC) relay, latching relay, slim / card relay, panel mount, socket mount and DIN rail relay styles for use in a wide range of process control applications.
Murrelektronik optocouplers and semiconductors are used to combine different signal levels or to isolate one signal from another. They are similar to a relay interface because they provide an optoelectronic signal transfer between input and output. Optocouplers and semiconductors have a long life span because they don't have any mechanical components that could wear out. They are suitable for applications with high switching frequencies, even over a long time.
A solid state relay switch is a control relay with isolated input and output, whose functions are achieved by means of electronic components without the use of moving parts such as those found in electromechanical relays.
These electronic relays are ideal for applications with many contact closures since solid state relay switches offer a greatly extended life compared to electromechanical relays.
Phase monitor relays provide protection against premature equipment failure caused by voltage faults on 3-phase systems. ProSense® phase monitor relays are compatible with typical Wye or Delta systems.
Voltage monitor relays protect equipment from damage caused by faults in a DC or 1-phase AC system, such as overvoltage, undervoltage, or exceeding a voltage band. These relays are available in a selection of voltage inputs; certain models offer fixed or adjustable drop-out protection.
Alternating relays are used in special applications where the optimization of load usage is required by equalizing the run time of two loads.
PSFR relays are designed to monitor the shaft seals of submersible pumps. The relay output can be used to give an alarm indication of a leaking seal. The relay will automatically reset when the fault condition clears.
The ISD Series of Intrinsically Safe Relays provide a safe and reliable method to control up to four loads (motor starters, relays, etc.) with up to four input devices (switches, sensors, etc.) located in a hazardous area.
The ISE Series of Intrinsically Safe Relays provide a safe and reliable method to control a single load (motor starters, relays, etc.) with a single input device switches, sensors, etc.) located in a hazardous area.
Timer relays provide simple time-based control, with multiple modes and adjustable timing ranges, discrete outputs, and a mechanical or electronic display. A variety of timers are available from well-known industry brands, such as Fuji, Dold, Murrelektronik, and AutomationDirect's own ProSense line.
Multi-function digital counters provide functions such as counter, timer, combination timer-counter or tachometer. Their LCD displays show present values, setting values and menu parameters for easy setup.