{"product_id":"1794-oa8i-allen-bradley-flex-i-o-8-channel-isolated-ac-module","title":"1794-OA8I Allen Bradley Flex I\/O 8 Channel Isolated AC Module","description":"\u003ch2\u003e\u003cb\u003e1794-OA8I Solid-State AC Output Architecture\u003c\/b\u003e\u003c\/h2\u003e\n\u003cp\u003eThe \u003cspan style=\"color: #0056b3;\"\u003e\u003cb\u003e1794-OA8I\u003c\/b\u003e\u003c\/span\u003e is an 8-channel solid-state isolated AC digital output module in the \u003cspan style=\"color: #0056b3;\"\u003e\u003cb\u003eAllen-Bradley Flex I\/O Series\u003c\/b\u003e\u003c\/span\u003e manufactured by Rockwell Automation. Designed for switching 120V AC field loads, this module provides channel-to-channel and channel-to-backplane galvanic isolation rated at 120V continuous (1250V AC dielectric withstand for 60 seconds). It supports up to 500 mA output current per channel, yielding a total module capacity of 4.0 A. Operating across an ambient temperature envelope of -20 to 55 °C, the module interface snaps onto compatible terminal bases including 1794-TB2, 1794-TB3, 1794-TB3S, 1794-TBN, and 1794-TBNF, requiring Keyswitch Position 8. Power dissipation ranges from 4.1W at 0.5A up to 6.3W at 1.0A maximum load, with 80 mA backplane current draw at 5V DC via the Flexbus network.\u003c\/p\u003e\n\u003ch3\u003e\u003cb\u003eTechnical Specifications Summary\u003c\/b\u003e\u003c\/h3\u003e\n\u003ctable style=\"width: 100%; border-collapse: collapse;\" border=\"1\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 8px;\"\u003e\u003cb\u003eManufacturer \/ Brand\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 8px;\"\u003eRockwell Automation \/ \u003cspan style=\"color: #0056b3;\"\u003e\u003cb\u003eAllen-Bradley\u003c\/b\u003e\u003c\/span\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 8px;\"\u003e\u003cb\u003eCatalog Part Number\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 8px;\"\u003e\u003cspan style=\"color: #0056b3;\"\u003e\u003cb\u003e1794-OA8I\u003c\/b\u003e\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 8px;\"\u003e\u003cb\u003eProduct Series\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 8px;\"\u003e\u003cspan style=\"color: #0056b3;\"\u003e\u003cb\u003eFlex I\/O Series\u003c\/b\u003e\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 8px;\"\u003e\u003cb\u003eModule Type\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 8px;\"\u003eIsolated AC Digital Output Module\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 8px;\"\u003e\u003cb\u003eOutput Channels\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 8px;\"\u003e8 Individually Isolated Outputs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 8px;\"\u003e\u003cb\u003eNominal Output Voltage\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 8px;\"\u003e120V AC (Operating range 85…132V AC, 47…63 Hz)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 8px;\"\u003e\u003cb\u003eCurrent Rating\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 8px;\"\u003e500 mA max per channel \/ 4.0 A total module aggregate\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 8px;\"\u003e\u003cb\u003eMinimum On-State Current\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 8px;\"\u003e5.0 mA per output channel\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 8px;\"\u003e\u003cb\u003eOn-State Voltage Drop\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 8px;\"\u003e1.0V AC max @ 0.5A load\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 8px;\"\u003e\u003cb\u003eOff-State Leakage Current\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 8px;\"\u003e2.25 mA max @ 120V AC\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 8px;\"\u003e\u003cb\u003eGalvanic Isolation Rating\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 8px;\"\u003e120V continuous (channel-to-channel \u0026amp; channel-to-backplane); 1250V AC for 60 s\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 8px;\"\u003e\u003cb\u003eFlexbus Power Draw\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 8px;\"\u003e80 mA @ 5V DC\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 8px;\"\u003e\u003cb\u003eThermal Dissipation\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 8px;\"\u003e14.0 BTU\/hr @ 0.5A load (Max 21.5 BTU\/hr @ 1.0A)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 8px;\"\u003e\u003cb\u003eCompatible Terminal Bases\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 8px;\"\u003e1794-TB2, 1794-TB3, 1794-TB3S, 1794-TBN, 1794-TBNF\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 8px;\"\u003e\u003cb\u003eBase Keyswitch Position\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 8px;\"\u003ePosition 8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 8px;\"\u003e\u003cb\u003eRecommended Overcurrent Protection\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 8px;\"\u003e1.6 A, 250V AC slow-blow field fuses\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 8px;\"\u003e\u003cb\u003eOperating Temperature Range\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 8px;\"\u003e-20 to 55 °C (-4 to 131 °F)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 8px;\"\u003e\u003cb\u003ePhysical Dimensions\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 8px;\"\u003e94 x 94 x 69 mm (3.7 x 3.7 x 2.7 in.)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003e\u003cb\u003eTarget Equipment \u0026amp; Field Integration Scenarios\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp\u003eThe solid-state design and individual channel isolation of the \u003cspan style=\"color: #0056b3;\"\u003e\u003cb\u003e1794-OA8I\u003c\/b\u003e\u003c\/span\u003e suit high-duty AC switching applications across diverse industrial control enclosures:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e120V AC solenoid valve actuation in pneumatic transport and water treatment systems\u003c\/li\u003e\n\u003cli\u003eInterfacing with magnetic contactor coils and motor starters without interposing relays\u003c\/li\u003e\n\u003cli\u003eDrive run\/stop and direction control signals operating on distinct AC power feeds\u003c\/li\u003e\n\u003cli\u003eMachine visual alarm columns, horns, and stack light indicators requiring fast cycle rates\u003c\/li\u003e\n\u003cli\u003eProcess control loops demanding isolated field wiring to isolate phase-to-phase AC circuits\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cb\u003eDiagnostic Features \u0026amp; Electrical Protection\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp\u003eReal-time visual feedback and electrical isolation maintain operational uptime and assist troubleshooting:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cb\u003eStatus LED Array:\u003c\/b\u003e Eight yellow field-side status LEDs illuminate when the corresponding output circuit receives active gate trigger signals.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eChannel-to-Channel Isolation:\u003c\/b\u003e Individual channel commons prevent cross-phase short circuits when switching loads fed from different AC transformers or phase legs.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eSolid-State Switching:\u003c\/b\u003e Triac-based solid-state outputs eliminate contact bounce and mechanical contact wear during high-frequency pulse operations.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cb\u003ePackaging, Fast Delivery \u0026amp; Guarantee\u003c\/b\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cb\u003eProduct Condition:\u003c\/b\u003e 100% Original, Factory Sealed Stock\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eWarranty Terms:\u003c\/b\u003e Full 12 Months Replacement Warranty\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eDispatch Window:\u003c\/b\u003e Same-day or next-business-day processing\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eGlobal Freight Options:\u003c\/b\u003e Express air shipping via FedEx, UPS, or DHL\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cb\u003eGlobal PLC Spare HUB's Insight\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp\u003eThe \u003cspan style=\"color: #0056b3;\"\u003e\u003cb\u003e1794-OA8I\u003c\/b\u003e\u003c\/span\u003e is an ideal solid-state alternative to relay output modules when rapid switching speeds or high duty cycles would prematurely wear out mechanical contacts. However, engineers must account for two triac characteristics during design: off-state leakage current and minimum on-state holding current. The 2.25 mA maximum leakage current can keep low-power loads—such as high-impedance digital inputs or high-efficiency LED indicators—partially energized when the channel is OFF. Conversely, field loads drawing under 5 mA will fail to latch the triac ON. Installing a parallel load resistor (bleeder resistor) across sensitive low-power field devices stabilizes both states and prevents ghost-voltage trips.\u003c\/p\u003e\n\u003ch3\u003e\u003cb\u003eFrequently Asked Questions (FAQ)\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cb\u003eQ: Why does a field load connected to the module stay energized or flicker when the channel status LED is turned OFF?\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eA:\u003c\/b\u003e Triac solid-state switches exhibit up to 2.25 mA off-state leakage current; on low-power loads like high-efficiency relays or LED indicators, this small leakage current is sufficient to maintain excitation, requiring an parallel AC load resistor to bleed off the residual voltage.\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eQ: How does wiring the terminal base differ for channel-isolated AC modules compared to non-isolated variants?\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eA:\u003c\/b\u003e Each isolated channel requires its own 120V AC hot leg connected to the designated odd terminal and its output load connected to the adjacent even terminal, ensuring zero common power bus connections across the 8 channels inside the base.\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eQ: What branch protection fuse size should be installed on the field power lines for this module?\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eA:\u003c\/b\u003e Install 1.6 A, 250V AC slow-blow fuses on field supply lines (or utilize a 1794-TBNF fused terminal base) to protect output circuits from thermal damage caused by load short circuits.\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eQ: Can this module switch 24V DC loads or low-voltage DC signals?\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eA:\u003c\/b\u003e No; triac output switches rely on the zero-crossing nature of alternating current (47…63 Hz) to turn off properly. Applying direct current (DC) will cause the output to lock in an permanently ON state once triggered.\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eQ: Selection Guide: When should I specify the 1794-OA8I solid-state module instead of the 1794-OW8 electromechanical relay module?\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eA:\u003c\/b\u003e Choose the \u003cspan style=\"color: #0056b3;\"\u003e\u003cb\u003e1794-OA8I\u003c\/b\u003e\u003c\/span\u003e for high-frequency switching operations on 120V AC loads where solid-state longevity is needed. Select the 1794-OW8 when switching DC voltages, dry contacts, or loads drawing less than 5 mA on-state current.\u003c\/p\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0722\/7863\/8774\/files\/1794-OA8I.png?v=1784617208\" alt=\"\"\u003e\u003c\/p\u003e","brand":"Allen-Bradley","offers":[{"title":"Default Title","offer_id":45013911109814,"sku":"1794-OA8I","price":137.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0722\/7863\/8774\/files\/1794-OA8I_810b7162-4af3-4e0b-bf02-e6edb29bda9c.jpg?v=1784617223","url":"https:\/\/www.plcsparehub.com\/products\/1794-oa8i-allen-bradley-flex-i-o-8-channel-isolated-ac-module","provider":"Global PLC Spare Hub","version":"1.0","type":"link"}