{"product_id":"allen-bradley-1756-a4-controllogix-chassis","title":"Allen-Bradley 1756-A4 ControlLogix Chassis","description":"\u003ch1 class=\"PDq2pG_selectionAnchorContainer\"\u003eAllen-Bradley 1756-A4 ControlLogix Chassis\u003cspan class=\"PDq2pG_selectionAnchor\"\u003e\u003c\/span\u003e\n\u003c\/h1\u003e\n\u003cp\u003eConfigured for backplane-based module hosting in ControlLogix architectures, the\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eAllen-Bradley 1756-A4\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003e(\u003cstrong\u003e1756-A4\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003ePLC chassis rack) provides direct electrical and data interconnection for Bulletin 1756 power supplies and I\/O modules across a 4-slot backplane structure within ControlLogix systems. The chassis requires an external power supply module to energize the backplane distribution network and supports horizontal back-panel mounting with fixed mechanical alignment for module-to-module communication.\u003c\/p\u003e\n\u003ch3\u003eHardware Specifications\u003c\/h3\u003e\n\u003ctable class=\"w-fit min-w-(--thread-content-width)\"\u003e\n\u003cthead\u003e\n\u003ctr class=\"firstRow\"\u003e\n\u003cth class=\"last:pe-10\"\u003eParameter\u003c\/th\u003e\n\u003cth class=\"last:pe-10\"\u003eSpecification\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\u003e1756-A4\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\u003e0.62 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOperating Temp\u003c\/td\u003e\n\u003ctd\u003e0 deg C to 60 deg C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePower Consumption\u003c\/td\u003e\n\u003ctd\u003e1.8 W (chassis dissipation)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSlots\u003c\/td\u003e\n\u003ctd\u003e4 module slots\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBackplane Power Requirement\u003c\/td\u003e\n\u003ctd\u003eExternal power supply required\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMounting Type\u003c\/td\u003e\n\u003ctd\u003eBack-panel mounting\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eStorage Temperature\u003c\/td\u003e\n\u003ctd\u003e-40 deg C to 85 deg C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHumidity\u003c\/td\u003e\n\u003ctd\u003e5 to 95% non-condensing\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eShock Rating\u003c\/td\u003e\n\u003ctd\u003e30 G operating \/ 50 G non-operating\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003eControlLogix Backplane Power Architecture and Slot Segmentation\u003c\/h3\u003e\n\u003cp\u003eThe 1756-A4 chassis implements a passive backplane distribution structure where all module communication and power routing is dependent on the installed 1756 power supply module. The 4-slot architecture defines a compact I\/O density boundary within ControlLogix systems, where each slot is electrically mapped to shared backplane voltage rails.\u003c\/p\u003e\n\u003cp\u003eBackplane segmentation enforces deterministic module communication across ControlLogix bus lines, with power distribution governed externally rather than chassis-internal regulation. This structure requires correct power supply pairing to maintain stable 5 VDC and system logic rail operation.\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions (FAQ)\u003c\/h3\u003e\n\u003cp\u003eQ: Can the 1756-A4 chassis operate without a power supply module installed?\u003cbr\u003eA: No. The chassis requires an external Bulletin 1756 power supply module to energize the backplane voltage rails and enable module operation.\u003c\/p\u003e\n\u003cp\u003eQ: Are all four slots electrically independent?\u003cbr\u003eA: No. All slots share a common backplane bus and power distribution structure defined by the installed power supply and module configuration.\u003c\/p\u003e\n\u003cp\u003eQ: Does the chassis support hot insertion of modules?\u003cbr\u003eA: Hot insertion depends on installed module type and system configuration. The backplane remains energized when powered, but module handling must follow ControlLogix safe insertion rules.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003cp\u003eMount the chassis on a rigid back panel using approved mechanical fasteners to maintain backplane connector alignment across all four slots. Ensure horizontal installation orientation to preserve backplane bus integrity and prevent mechanical stress on module connectors.\u003c\/p\u003e\n\u003cp\u003eInstall a compatible ControlLogix Bulletin 1756 power supply prior to module population. Maintain separation between power wiring and signal cabling to reduce backplane noise coupling. Ensure enclosure grounding continuity before energizing the system.\u003c\/p\u003e","brand":"Allen-Bradley","offers":[{"title":"Default Title","offer_id":43568988880986,"sku":"1756-A4","price":123.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0612\/4601\/3530\/files\/1756-A42.jpg?v=1782712198","url":"https:\/\/www.plcmasters.com\/products\/allen-bradley-1756-a4-controllogix-chassis","provider":"PLC Masters Ltd.","version":"1.0","type":"link"}