Input & Output Interfaces


Input/output or I/O interface is the interaction between a central processing device, such as a PLC, and input and output devices. Inputs are the signals or data received by the processing system from a digital input device, such as a switch, relay or contactor, and analog inputs from various sensors indicating the status of physical parameters, such as temperature, pressure etc. Outputs are the signals or data sent from the processing system to digital output devices, such as an indicator, lamp, alarm, relay or contactor and analog output devices, such as motors, valves and Proportional Controllers etc.


Switch and Indicator Switches

A switch is an electrical component that can "make" or "break" an electrical circuit, interrupting the current or diverting it from one conductor to another. The mechanism of a switch removes or restores the conducting path in a circuit when it is operated. It may be operated manually, for example, a light switch or a keyboard button, may be operated by a moving object such as a door, or may be operated by some sensing element for pressure, temperature or flow.


Relays

A relay is an electrically operated switch. Many relays use an electromagnet to mechanically operate a switch, but other operating principles are also used, such as solid-state relays. Relays are used where it is necessary to control a circuit by a separate low-power signal, or where several circuits must be controlled by one signal.


Indicators (LED, lamps, beacon/emergency/stop lamps)

Emergency lamp, signal tower lights, indicator lights, andon lights, warning lights, industrial signal lights, tower lights, beacon and light towers are commonly used on equipment in industrial manufacturing and process control environments to provide visual indicators of a machine state or process event to machine operators, technicians, production managers and factory personnel.


Contactors

A contactor is an electrically controlled switch used for switching an electrical power circuit, similar to a relay except with higher current ratings and a few other differences. A contactor is typically controlled by a circuit which has a much lower power level than the switched circuit, such as a 24-volt coil electromagnet controlling a 220-volt motor switch.


Return to main Industrial Automation Control page

Videos

High-Quality, Energy-Efficient Industrial LED Lighting Provides Bright, Even Illumination

Panasonic EV Relays

SIRIUS Compact Starter 3RA6

Featured Products

MULTICOMP PRO

New Ethernet Switches

Shop Now
EATON MOELLER

EASY-E4 PLC

Shop Now
SIEMENS

Touch screens and HMIs - SIMATIC Series

Shop Now
BRAINBOXES

Neuron Edge Industrial IoT Pi Controller

Shop Now
Compare Selected Compare Add Selected Add

Contract pricing display is unavailable at the moment. Prices shown are standard retail prices, orders placed will have contract pricing applied when processed.

  Manufacturer Part No Order Code Manufacturer / Description
Availability Price For
Price
Quantity
RT424024
RT424024 - Power Relay, DPDT, 24 VDC, 8 A, RT2 Series, Through Hole, Non Latching

1629054

Power Relay, DPDT, 24 VDC, 8 A, RT2 Series, Through Hole, Non Latching

SCHRACK - TE CONNECTIVITY

RELAY, DPDT, 250VAC, 8A; Contact Configuration:DPDT; Coil Voltage:24VDC; Contact Current:8A; Product Range:RT2 Series; Relay Mounting:Through Hole; Coil Type:Non Latching; Contact Voltage VAC:250VAC; Relay Terminals:Solder; Contact Voltage VDC:-; Contact

  • 22,223 available for 3 - 4 business days delivery
  • 11,818 available for 4 - 5 business days delivery
+ Check Stock & Lead Times

  • 22,223 available for 3 - 4 business days delivery: (UK stock) Order before 7:35pm Mon – Fri. (Excluding National Holidays)
  • 11,818 available for 4 - 5 business days delivery: (US stock) Order before 6:00pm Mon – Fri. (Excluding National Holidays)

  • 10 more will be available on 4/11/20
  • More stock available week commencing 7/12/20

    Restricted Item
    DM1-02P-30-3
    DM1-02P-30-3 - Microswitch, Snap Action, Lever, SPDT, Solder, 1 A, 5 VDC

    1735365

    Microswitch, Snap Action, Lever, SPDT, Solder, 1 A, 5 VDC

    MULTICOMP PRO

    MICROSWITCH, SPDT, 1A, SIM LEVER; Microswitch Type:Snap Action; Microswitch Actuator:Lever; Contact Configuration:SPDT; Switch Terminals:Solder; Contact Current Max:1A; Contact Voltage DC Nom:5VDC; Product Range:DM1 Series; Contact Voltage AC Nom:125VAC;

    • 9,898 available for 3 - 4 business days delivery
    • 105 available for 4 - 5 business days delivery
    + Check Stock & Lead Times

    • 9,898 available for 3 - 4 business days delivery: (UK stock) Order before 7:35pm Mon – Fri. (Excluding National Holidays)
    • 105 available for 4 - 5 business days delivery: (US stock) Order before 6:00pm Mon – Fri. (Excluding National Holidays)

    More stock available week commencing 22/02/21

    Restricted Item
    DM1-01P-30-3
    DM1-01P-30-3 - Microswitch, Subminiature, Short Lever, SPDT, Solder, 1 A, 5 VDC

    1735364

    Microswitch, Subminiature, Short Lever, SPDT, Solder, 1 A, 5 VDC

    MULTICOMP PRO

    MICROSWITCH, SPDT, 1A, SHORT LEVER, 125V; Microswitch Type:Snap Action; Microswitch Actuator:Short Lever; Contact Configuration:SPDT; Switch Terminals:Solder; Contact Current Max:1A; Contact Voltage DC Nom:5VDC; Product Range:DM1 Series; Contact Voltage

    • 12,434 available for 1 - 2 business days delivery
    • 1,367,261 available for 3 - 4 business days delivery
    + Check Stock & Lead Times

    • 12,434 available for 1 - 2 business days delivery: (SG stock) Order before 4:30pm Mon – Fri. (Excluding National Holidays)
    • 1,367,261 available for 3 - 4 business days delivery: (UK stock) Order before 7:35pm Mon – Fri. (Excluding National Holidays)

    More stock available week commencing 22/02/21

    Restricted Item
    RTE24005
    RTE24005 - General Purpose Relay, RT2 Series, Power, Non Latching, DPDT, 5 VDC, 8 A

    1703727

    General Purpose Relay, RT2 Series, Power, Non Latching, DPDT, 5 VDC, 8 A

    POTTER&BRUMFIELD - TE CONNECTIVITY

    RELAY, DPDT, 250VAC, 5VDC, 3A; Contact Configuration:DPDT; Coil Voltage:5VDC; Contact Current:8A; Product Range:RT2 Series; Relay Mounting:Through Hole; Coil Type:Non Latching; Contact Voltage VAC:250VAC; Relay Terminals:Solder; Contact Voltage VDC:24VD

    • 6,306 available for 3 - 4 business days delivery
    • 720 available for 4 - 5 business days delivery
    + Check Stock & Lead Times

    • 6,306 available for 3 - 4 business days delivery: (UK stock) Order before 7:35pm Mon – Fri. (Excluding National Holidays)
    • 720 available for 4 - 5 business days delivery: (US stock) Order before 6:00pm Mon – Fri. (Excluding National Holidays)

  • 500 more will be available on 1/11/20
  • More stock available week commencing 4/01/21

    Restricted Item
    RTD14012
    RTD14012 - General Purpose Relay, Power PCB Relay RT1 Series, Power, Non Latching, SPDT, 12 VDC, 16 A

    1175016

    General Purpose Relay, Power PCB Relay RT1 Series, Power, Non Latching, SPDT, 12 VDC, 16 A

    TE CONNECTIVITY

    RELAY, SPDT, 250VAC, 16A; Contact Configuration:SPDT; Coil Voltage:12VDC; Contact Current:16A; Product Range:RT1 Series; Relay Mounting:Through Hole; Coil Type:DC; Contact Voltage VAC:250VAC; Relay Terminals:Solder; Contact Voltage VDC:-; Contact Materia

    • 10,701 available for 3 - 4 business days delivery
    + Check Stock & Lead Times

    • 10,701 available for 3 - 4 business days delivery: (UK stock) Order before 7:35pm Mon – Fri. (Excluding National Holidays)

  • 519 more will be available on 1/11/20
  • 13,428 more will be available on 8/03/21
  • More stock available week commencing 17/05/21

    Restricted Item
    M140T01-AE0507A
    M140T01-AE0507A - Microswitch, Snap Action, Long Lever, SPDT, Solder, 5 A

    1735352

    Microswitch, Snap Action, Long Lever, SPDT, Solder, 5 A

    MULTICOMP PRO

    MICROSWITCH, SPDT, 5A, LONG LEVER; Microswitch Type:Snap Action; Microswitch Actuator:Long Lever; Contact Configuration:SPDT; Switch Terminals:Solder; Contact Current Max:5A; Contact Voltage DC Nom:-; Product Range:M140T01 Series; Contact Voltage AC Nom:

    • 4,069 available for 3 - 4 business days delivery
    + Check Stock & Lead Times

    • 4,069 available for 3 - 4 business days delivery: (UK stock) Order before 7:35pm Mon – Fri. (Excluding National Holidays)

    More stock available week commencing 22/02/21

    Restricted Item
    RT314615
    RT314615 - General Purpose Relay, Power PCB Relay RT1 Series, Power, Non Latching, SPDT, 115 VAC, 16 A

    1629048

    General Purpose Relay, Power PCB Relay RT1 Series, Power, Non Latching, SPDT, 115 VAC, 16 A

    SCHRACK - TE CONNECTIVITY

    RELAY, SPDT, 250VAC, 16A; Contact Configuration:SPDT; Coil Voltage:115VAC; Contact Current:16A; Product Range:RT1 Series; Relay Mounting:Through Hole; Coil Type:Non Latching; Contact Voltage VAC:250VAC; Relay Terminals:Solder; Contact Voltage VDC:-; Cont

    • 19,399 available for 3 - 4 business days delivery
    + Check Stock & Lead Times

    • 19,399 available for 3 - 4 business days delivery: (UK stock) Order before 7:35pm Mon – Fri. (Excluding National Holidays)

    More stock available week commencing 1/02/21

    Restricted Item
    V7-1V19E9
    V7-1V19E9 - Microswitch, Miniature, Pin Plunger, SPDT, Quick Connect, 21 A

    1796579

    Microswitch, Miniature, Pin Plunger, SPDT, Quick Connect, 21 A

    HONEYWELL

    MICROSWITCH, PIN, SPDT, 277VAC, 21A; Microswitch Type:Miniature; Microswitch Actuator:Pin Plunger; Contact Configuration:SPDT; Switch Terminals:Quick Connect; Contact Current Max:21A; Contact Voltage DC Nom:-; Product Range:V7 Series; Contact Voltage AC

    • 739 available for 3 - 4 business days delivery
    • 11,234 available for 4 - 5 business days delivery
    + Check Stock & Lead Times

    • 739 available for 3 - 4 business days delivery: (UK stock) Order before 7:35pm Mon – Fri. (Excluding National Holidays)
    • 11,234 available for 4 - 5 business days delivery: (US stock) Order before 6:00pm Mon – Fri. (Excluding National Holidays)

    More stock available week commencing 7/12/20

    Restricted Item
    SSM-001
    SSM-001 - Microswitch, Snap Action, Lever, SPDT, Solder, 500 mA, 30 VDC

    1735368

    Microswitch, Snap Action, Lever, SPDT, Solder, 500 mA, 30 VDC

    MULTICOMP PRO

    MICROSWITCH, SPDT, 0.5A, PLASTIC LEVER; Microswitch Type:Snap Action; Microswitch Actuator:Lever; Contact Configuration:SPDT; Switch Terminals:Solder; Contact Current Max:500mA; Contact Voltage DC Nom:30VDC; Product Range:-; Contact Voltage AC Nom:-; Ope

    • 18,185 available for 3 - 4 business days delivery
    + Check Stock & Lead Times

    • 18,185 available for 3 - 4 business days delivery: (UK stock) Order before 7:35pm Mon – Fri. (Excluding National Holidays)

    More stock available week commencing 15/02/21

    Restricted Item