{"product_id":"1746-ow4-allen-bradley-4-point-n-o-relay-output-module-for-slc-500","title":"1746-OW4 Allen-Bradley 4-Point N.O. Relay Output Module for SLC 500","description":"\u003ch3\u003e\u003cb\u003e1746-OW4 | Four-Point Relay Output for SLC 500\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp\u003eThe \u003cb\u003eAllen-Bradley 1746-OW4\u003c\/b\u003e is a four-point, normally open relay contact output module for the \u003cb\u003eSLC 500\u003c\/b\u003e programmable controller platform. Its electromechanical contacts switch compatible AC or DC field circuits, making it useful where a dry-contact switching interface is required.\u003c\/p\u003e\n\u003cp\u003eUnlike a solid-state output, a relay contact can switch either AC or DC within its specified ratings. Selection must account for load voltage, current, switching frequency, and the electrical characteristics of the connected device.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cb\u003eRelay Contact Layout\u003c\/b\u003e\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cb\u003e4 normally open (N.O.) contacts:\u003c\/b\u003e each output closes when its relay is energized and opens when de-energized.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cb\u003eAC\/DC switching:\u003c\/b\u003e stated operating ranges are 5–265V AC and 5–125V DC. These are voltage ranges, not a guarantee that every load can be switched at every voltage.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cb\u003eFour common points:\u003c\/b\u003e confirm the terminal arrangement and circuit grouping from the module’s wiring diagram before connecting field loads.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cb\u003eElectromechanical switching:\u003c\/b\u003e contact operation involves mechanical movement and is subject to relay life, load type, and switching frequency.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cb\u003eTechnical Specifications\u003c\/b\u003e\u003c\/h3\u003e\n\u003ctable\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003cth\u003eManufacturer\u003c\/th\u003e\n\u003ctd\u003eRockwell Automation\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003ctd\u003eAllen-Bradley\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eCatalog Number\u003c\/th\u003e\n\u003ctd\u003e\u003cb\u003e1746-OW4\u003c\/b\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eSeries\u003c\/th\u003e\n\u003ctd\u003eSLC 500\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eModule Type\u003c\/th\u003e\n\u003ctd\u003eDigital relay contact output module\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eOutput Count\u003c\/th\u003e\n\u003ctd\u003e4\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eContact Type\u003c\/th\u003e\n\u003ctd\u003eNormally open (N.O.) relay contacts\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eOperating Voltage\u003c\/th\u003e\n\u003ctd\u003e5–265V AC or 5–125V DC, as supplied\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eCurrent per Output\u003c\/th\u003e\n\u003ctd\u003e1.5A at 120V AC; 1.2A at 24V DC, as supplied\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eMaximum Continuous Current per Module\u003c\/th\u003e\n\u003ctd\u003e8A, as supplied; verify applicable channel and load derating in the manual\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eBackplane Current\u003c\/th\u003e\n\u003ctd\u003e45mA, as supplied\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eMinimum Load Current\u003c\/th\u003e\n\u003ctd\u003e1mA at 5V DC, as supplied\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eResponse \/ Delay\u003c\/th\u003e\n\u003ctd\u003eSource data lists 60ms in and 2.5ms out; another supplied description states 10ms for both ON and OFF. Verify the correct timing specification for the module revision.\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eMaximum Thermal Dissipation\u003c\/th\u003e\n\u003ctd\u003e1.9W, as supplied\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eHeat Dissipation per Point\u003c\/th\u003e\n\u003ctd\u003e0.133W, as supplied\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eApplication\u003c\/th\u003e\n\u003ctd\u003eRelay contact output switching\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003ci\u003eSpecification check: The supplied information contains differing response-time figures and describes backplane current at both 5V and 24V in one passage. Confirm these values against the applicable Allen-Bradley 1746-OW4 technical documentation before using them for timing, power-budget, or design calculations. Also verify contact ratings for the actual load type, including inductive loads.\u003c\/i\u003e\u003c\/p\u003e\n\n\u003ch3\u003e\u003cb\u003eWhere This Module Fits\u003c\/b\u003e\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cb\u003eSLC 500 control panels:\u003c\/b\u003e adds relay-based discrete output points to a compatible SLC 500 rack.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cb\u003eAC control circuits:\u003c\/b\u003e switches suitable pilot devices, interface relays, and other AC loads within the documented contact ratings.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cb\u003eDC control circuits:\u003c\/b\u003e switches compatible DC loads where the voltage, current, and load characteristics meet the relay’s ratings.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cb\u003eMachine sequencing:\u003c\/b\u003e supports PLC-controlled enable, run, status, and interlock-related signals when the application does not require a safety-rated output.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cb\u003eLegacy equipment maintenance:\u003c\/b\u003e serves as a replacement or additional relay-output module after checking the installed rack, wiring, and configuration.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cb\u003eApplication boundary:\u003c\/b\u003e The 1746-OW4 is a standard control output module, not a safety-rated switching device. Do not use it as the sole means of emergency stopping, personnel protection, or isolation. Use an appropriately engineered safety circuit where required.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cb\u003ePanel Design and Installation Notes\u003c\/b\u003e\u003c\/h3\u003e\n\u003col\u003e\n  \u003cli\u003e\n\u003cb\u003eCheck the rack and slot:\u003c\/b\u003e confirm that the SLC 500 chassis and controller configuration support the module and that the replacement matches the original catalog number.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cb\u003eReview contact ratings:\u003c\/b\u003e identify whether each load is resistive, inductive, or capacitive. Motor starters, solenoid coils, and contactor coils may require suitable suppression or an interface relay.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cb\u003eSeparate circuits correctly:\u003c\/b\u003e observe the module’s common-terminal arrangement and applicable AC\/DC wiring practices. Do not assume the contacts provide isolation beyond the manufacturer’s stated ratings.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cb\u003eEstimate switching duty:\u003c\/b\u003e frequent cycling can shorten relay contact life. Consider switching frequency and expected service life when selecting the output architecture.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cb\u003eDe-energize before wiring:\u003c\/b\u003e disconnect and verify all relevant field and control power before installation or terminal work. Follow the applicable manual and site lockout\/tagout procedure.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch3\u003e\u003cb\u003eField Diagnostics: Trace the Signal from Logic to Load\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp\u003eWhen a commanded output fails to switch, isolate the fault systematically rather than immediately replacing the module.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cb\u003eConfirm the PLC command:\u003c\/b\u003e check the controller mode, program logic, output address, and online status.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cb\u003eInspect the output indication:\u003c\/b\u003e where available, compare the module’s status indication with the commanded state. An indicator does not by itself prove that the field contact is conducting.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cb\u003eMeasure the field circuit:\u003c\/b\u003e use an appropriately rated meter to verify the supply and check voltage across the contact and load under the commanded condition.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cb\u003eCheck contact and wiring condition:\u003c\/b\u003e inspect for loose terminals, damaged conductors, contact wear, or a load-side open circuit. A relay can actuate mechanically while its contacts fail electrically.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cb\u003eCheck load compatibility:\u003c\/b\u003e confirm that current demand, inrush, and inductive transients are within the documented limits. Review suppression components and the load’s actual operating voltage.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cb\u003eLook for environmental deterioration:\u003c\/b\u003e the supplied description warns that chemical exposure may affect sealing materials. Inspect the installation environment and module condition periodically; replace a degraded unit according to maintenance procedures.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eFor continuity testing, isolate the module and field circuit from all power sources first. Do not use an ohmmeter on an energized circuit.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cb\u003eGlobal PLC Spare HUB Review\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp\u003eThe 1746-OW4 is most relevant when a legacy SLC 500 application needs relay contacts rather than transistor-based DC switching. The practical selection issue is not simply “AC or DC”: contact life and switching reliability depend strongly on the load. A small resistive pilot load and an inductive coil can impose very different demands on the same relay contact.\u003c\/p\u003e\n\u003cp\u003eFor a replacement purchase, compare the installed catalog number, rack position, terminal wiring, field voltage, and load current. If the existing module switches inductive devices or cycles frequently, review suppression and relay-duty requirements before commissioning the spare.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cb\u003eWarranty and Shipping\u003c\/b\u003e\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cb\u003eWarranty:\u003c\/b\u003e 12 months.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cb\u003eShipping carriers:\u003c\/b\u003e FedEx, UPS, and DHL, subject to destination and shipment arrangements.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cb\u003eQuote information:\u003c\/b\u003e include catalog number \u003cb\u003e1746-OW4\u003c\/b\u003e, quantity, destination, and any required condition or packaging details.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cb\u003eFrequently Asked Questions\u003c\/b\u003e\u003c\/h3\u003e\n\n\u003cp\u003e\u003cb\u003e1. How can I tell whether a relay output is failing or the field device is faulty?\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003eCheck the PLC command first, then measure the circuit at the relay output and load. If the relay is commanded but the contact does not pass the expected voltage, investigate the contact, terminal, and wiring. If the correct voltage reaches the load, test the field device and its return path.\u003c\/p\u003e\n\n\u003cp\u003e\u003cb\u003e2. What should I consider when switching a solenoid or contactor coil?\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003eConfirm the coil’s voltage and steady-state current, then check its inrush and inductive characteristics against the module’s contact ratings. Use suitable suppression where specified by the coil or control-system manufacturer. Do not select solely by the nominal current printed on the load.\u003c\/p\u003e\n\n\u003cp\u003e\u003cb\u003e3. Is a relay output preferable to a transistor output for every AC\/DC application?\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003eNo. Relay contacts can support compatible AC and DC circuits, but they have mechanical wear and switching-life limits. Transistor outputs may be better for frequent, fast DC switching. Select the output type based on voltage, load, switching rate, isolation needs, and maintenance strategy.\u003c\/p\u003e\n\n\u003cp\u003e\u003cb\u003e4. What information should I provide when requesting a replacement quotation?\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003eProvide the full catalog number, SLC 500 chassis and controller details, the number of points required, field voltage, load current, and the nature of the loads. A clear photo of the existing module label and terminal wiring can help verify the replacement match.\u003c\/p\u003e\n\n\u003cp\u003e\u003cb\u003e5. Why might a relay module work during a test but fail after returning to production?\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003eThe production load may have higher inrush, inductive transients, or a greater switching frequency than the test setup. Review the actual load duty, contact rating, suppression, and environmental exposure. A low-current bench test may not reveal contact degradation under the machine’s normal operating conditions.\u003c\/p\u003e","brand":"Allen-Bradley","offers":[{"title":"Default Title","offer_id":45013897281718,"sku":"1746-OW4","price":135.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0722\/7863\/8774\/files\/1746-OW4_cf770d8e-bf27-4854-bfe4-046ba85361cb.jpg?v=1792475629","url":"https:\/\/www.plcsparehub.com\/products\/1746-ow4-allen-bradley-4-point-n-o-relay-output-module-for-slc-500","provider":"Global PLC Spare Hub","version":"1.0","type":"link"}