{"product_id":"1791-24br-allen-bradley-24-input-8-relay-output-dc-block-i-o","title":"1791-24BR Allen-Bradley 24 Input 8 Relay Output DC Block I\/O","description":"\u003ch2\u003e\u003cstrong\u003e1791-24BR Allen‑Bradley 24‑Input 8‑Relay Output DC Block I\/O\u003c\/strong\u003e\u003c\/h2\u003e\n\u003ch3\u003eKey Technical Specifications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan style=\"color: #b22222;\"\u003e\u003cstrong\u003eManufacturer:\u003c\/strong\u003e Allen‑Bradley.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"color: #b22222;\"\u003e\u003cstrong\u003eModel:\u003c\/strong\u003e 1791-24BR\u003c\/span\u003e – 24‑point DC input \/ 8‑point relay output Block I\/O.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInput voltage range:\u003c\/strong\u003e 10‑30V DC (on‑state), with 11 mA max at 30V. Off‑state below 5V DC provides high noise immunity.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInput current:\u003c\/strong\u003e minimum 2.5 mA at 10V DC guarantees reliable turn‑on; maximum 11 mA at 30V DC.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOutput relays:\u003c\/strong\u003e 8 form A (normally open) contacts. They switch 20‑132V AC at 1 A resistive – ideal for mixed voltage panels.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExternal power requirement:\u003c\/strong\u003e 19.2‑30V DC at 300 mA to supply the module logic and inputs.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIsolation ratings:\u003c\/strong\u003e 500V AC between power supply, remote I\/O, I\/O groups, and logic – prevents ground loops.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePower dissipation:\u003c\/strong\u003e 14.5 W max (49.4 BTU\/h) – ensure adequate ventilation in the enclosure.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEnvironmental range:\u003c\/strong\u003e operate 0 °C to 60 °C, store ‑40 °C to 85 °C, 5‑95 % humidity non‑condensing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDimensions \u0026amp; weight:\u003c\/strong\u003e 176.5 x 110.5 x 98 mm (6.95 x 4.35 x 3.85 in), 2.38 lb (1.08 kg).\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eInstallation and Wiring Guidelines\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eMount the \u003cstrong\u003e1791-24BR\u003c\/strong\u003e vertically on a DIN rail as recommended – this optimises heat dissipation and derating.\u003c\/li\u003e\n\u003cli\u003eWire the 24 DC inputs in three groups of eight; each group shares a common terminal for efficient field wiring.\u003c\/li\u003e\n\u003cli\u003eConnect an external 19.2‑30V DC power supply to the dedicated terminals – the module draws 300 mA max.\u003c\/li\u003e\n\u003cli\u003eRelay outputs are volt‑free contacts: you can connect AC or DC loads up to 132V AC \/ 1 A resistive.\u003c\/li\u003e\n\u003cli\u003eUse copper conductors rated 75 °C; tighten terminals to 0.8 Nm (7 lb‑in).\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eCompatible Controllers and Diagnostics\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eThe \u003cstrong\u003e1791-24BR\u003c\/strong\u003e works with PLC‑2, PLC‑3, PLC‑5\/250, PLC‑5 family, and SLC 5\/02 modular controllers.\u003c\/li\u003e\n\u003cli\u003eBuilt‑in status LEDs show communication health and I\/O states – simplifies troubleshooting.\u003c\/li\u003e\n\u003cli\u003eTwo switch assemblies let you configure rack number, baud rate, starting I\/O group, and last state behaviour.\u003c\/li\u003e\n\u003cli\u003eTerminal strips on both sides provide easy access to remote I\/O link, I\/O wiring, and power connections.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003ePackage Contents\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eOne Allen‑Bradley \u003cstrong\u003e1791-24BR\u003c\/strong\u003e Block I\/O module with factory‑attached terminal blocks.\u003c\/li\u003e\n\u003cli\u003eQuick reference guide for wiring and switch settings.\u003c\/li\u003e\n\u003cli\u003eMounting instructions and compliance information.\u003c\/li\u003e\n\u003cli\u003eAll items ship in anti‑static protective packaging.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eFrequently Asked Questions (FAQ)\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCan the \u003cstrong\u003e1791-24BR\u003c\/strong\u003e outputs switch DC voltage?\u003c\/strong\u003e Yes, the relay contacts are potential‑free. For DC loads the voltage must stay within the contact rating (30V DC \/ 1 A max).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWhat is the minimum input current for a reliable ON state?\u003c\/strong\u003e At 10V DC the input draws at least 2.5 mA, which ensures a solid logic transition.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDoes the module include the power supply?\u003c\/strong\u003e No, you need an external 19.2‑30V DC supply (300 mA minimum) to power the module electronics.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHow do I set the I\/O rack number on the \u003cstrong\u003e1791-24BR\u003c\/strong\u003e?\u003c\/strong\u003e Use the two rotary switch assemblies located on the front panel – they adjust rack number, baud rate, and last chassis settings.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWhat is the isolation between input groups?\u003c\/strong\u003e 500V AC between groups and logic – this protects against voltage surges in different sections of the machine.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp style=\"margin-top: 20px;\"\u003eFor inquiries or to place an order, contact us at \u003ca href=\"mailto:sales@nex-auto.com\"\u003esales@nex-auto.com\u003c\/a\u003e or \u003ca href=\"https:\/\/wa.me\/8615392429628\" target=\"_blank\"\u003e+86 153 9242 9628 (WhatsApp)\u003c\/a\u003e.\u003cbr\u003ePartner: \u003ca href=\"https:\/\/www.nex-auto.com\/\" target=\"_blank\"\u003eNexAuto Technology Limited\u003c\/a\u003e\u003c\/p\u003e","brand":"Allen-Bradley","offers":[{"title":"Default Title","offer_id":45836500533409,"sku":"1791-24BR","price":240.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0673\/5390\/3265\/files\/1791-24BR.jpg?v=1780645769","url":"https:\/\/www.autonexcontrol.com\/products\/1791-24br-allen-bradley-24-input-8-relay-output-dc-block-i-o","provider":"AutoNex Controls Limited ","version":"1.0","type":"link"}