{"product_id":"allen-bradley-1771-a4b-plc-5-universal-i-o-chassis","title":"Allen-Bradley 1771-A4B PLC-5 Universal I\/O Chassis","description":"\u003cp\u003eThe \u003cstrong\u003eAllen-Bradley 1771-A4B\u003c\/strong\u003e, also cataloged as the \u003cstrong\u003e1771-A4B\u003c\/strong\u003e PLC Chassis, operates as a dedicated hardware component for physical module housing and backplane power distribution within Allen-Bradley PLC-5 systems. It provides structural mounting and high-speed internal bus connectivity across 16 module slots to facilitate signal exchange between processors and I\/O modules.\u003c\/p\u003e\n\u003ch3\u003eHardware Specifications\u003c\/h3\u003e\n\u003cfigure class=\"table\"\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003e\u003cstrong\u003eParameter\u003c\/strong\u003e\u003c\/th\u003e\n\u003cth\u003e\u003cstrong\u003eSpecification\u003c\/strong\u003e\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eModel\u003c\/td\u003e\n\u003ctd\u003e1771-A4B\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBrand\u003c\/td\u003e\n\u003ctd\u003eAllen-Bradley\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOrigin\u003c\/td\u003e\n\u003ctd\u003eUSA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWeight\u003c\/td\u003e\n\u003ctd\u003e13.36 lbs (6.06 kg)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDimensions\u003c\/td\u003e\n\u003ctd\u003eStandard 16-slot Allen-Bradley 1771 Chassis Form Factor\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOperating Temp\u003c\/td\u003e\n\u003ctd\u003e0 to 60 deg C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePower Consumption\u003c\/td\u003e\n\u003ctd\u003ePassive chassis backplane (supplies up to 24 A at 5.25 VDC)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSlot Capacity\u003c\/td\u003e\n\u003ctd\u003e16 Slots\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaximum Current Rating\u003c\/td\u003e\n\u003ctd\u003e24 A backplane capacity\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eVoltage Rating\u003c\/td\u003e\n\u003ctd\u003e5.25 VDC backplane bus\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubsystem Type\u003c\/td\u003e\n\u003ctd\u003eUniversal I\/O Chassis\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/figure\u003e\n\u003ch3\u003eBackplane Bus Communication Velocity \u0026amp; I\/O Density Scaling\u003c\/h3\u003e\n\u003cp\u003eThe 1771-A4B Universal I\/O Chassis enables high backplane bus communication velocity and supports maximum I\/O density scaling across complex industrial control architectures. Its integrated multi-slot backplane traces maintain low-impedance power distribution up to 24 A at 5.25 VDC while insulating high-speed parallel data lines against internal cross-talk. Dedicated slot keying prevents hardware damage by ensuring only compatible PLC-5 processor, communication, and 1771 I\/O modules can seat into assigned positions.\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003eQ: What power limits govern module selection in the 1771-A4B chassis?\u003c\/p\u003e\n\u003cp\u003eA: The total current draw of all installed modules must not exceed the chassis maximum backplane current rating of 24 A at 5.25 VDC, as supplied by the external power supply unit.\u003c\/p\u003e\n\u003cp\u003eQ: Can the 1771-A4B chassis accommodate both 1-slot and 2-slot addressing modes?\u003c\/p\u003e\n\u003cp\u003eA: Yes, the chassis backplane supports 2-slot, 1-slot, and 1\/2-slot I\/O addressing modes configured via backplane DIP switch settings on the chassis frame.\u003c\/p\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003col\u003e\n\u003cli\u003e\n\u003cstrong\u003ePhysical Mounting:\u003c\/strong\u003e Mount the 1771-A4B chassis securely in an industrial enclosure using standard mounting screws. Ensure adequate vertical clearance for convection airflow across all 16 slots.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBackplane Power Connection:\u003c\/strong\u003e Connect the designated external power supply module to the chassis power harness, ensuring proper polarity and secure terminal tightening to support 5.25 VDC distribution.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGrounding Protocols:\u003c\/strong\u003e Wire a heavy-gauge copper grounding strap from the ground stud on the chassis frame directly to the main enclosure earth ground bar to eliminate electrostatic discharge risks.\u003c\/li\u003e\n\u003c\/ol\u003e","brand":"Allen-Bradley","offers":[{"title":"Default Title","offer_id":52678034424088,"sku":"1771-A4B","price":270.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0892\/3483\/3688\/files\/1771-A4B_Cocoai.jpg?v=1789373906","url":"https:\/\/www.innoplcsync.com\/products\/allen-bradley-1771-a4b-plc-5-universal-i-o-chassis","provider":"InnoPLC Sync Co., Ltd.","version":"1.0","type":"link"}