{"product_id":"allen-bradley-1756-cnb-b-controllogix-controlnet-communication-module","title":"Allen-Bradley 1756-CNB\/B ControlLogix ControlNet Communication Module","description":"\u003ch1 class=\"PDq2pG_selectionAnchorContainer\"\u003eAllen-Bradley 1756-CNB\/B ControlLogix ControlNet Communication Module\u003cspan class=\"PDq2pG_selectionAnchor\"\u003e\u003c\/span\u003e\n\u003c\/h1\u003e\n\u003cp\u003eConfigured for deterministic ControlNet frame exchange within ControlLogix chassis architectures, the\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eAllen-Bradley 1756-CNB\/B\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003e(\u003cstrong\u003e1756-CNB\/B\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eControlNet Communication Module) provides direct physical and protocol-level interfacing between ControlLogix backplane logic and a single-channel ControlNet network operating at scheduled data transmission rates. The module supports up to 99 ControlNet connections with coordinated cyclic and unscheduled traffic handling.\u003c\/p\u003e\n\u003cp\u003eWithin the\u003cspan\u003e \u003c\/span\u003e\u003cspan class=\"hover:entity-accent entity-underline inline cursor-pointer align-baseline\"\u003eRockwell Automation\u003c\/span\u003e\u003cspan\u003e \u003c\/span\u003eControlLogix communication stack, the module executes backplane-to-network mapping for ControlNet nodes using deterministic scheduling logic managed through the chassis communication subsystem.\u003c\/p\u003e\n\u003chr\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-CNB\/B\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\u003eNetwork Type\u003c\/td\u003e\n\u003ctd\u003eControlNet single channel\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eConnections\u003c\/td\u003e\n\u003ctd\u003eUp to 99\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eIsolation\u003c\/td\u003e\n\u003ctd\u003e30 V continuous basic insulation (ControlNet to backplane, USB to backplane)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eElectromagnetic Immunity\u003c\/td\u003e\n\u003ctd\u003e10 V\/m (80–2000 MHz), 3 V\/m (2000–2700 MHz)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompliance\u003c\/td\u003e\n\u003ctd\u003eIndustrial EMC standards\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRepairability\u003c\/td\u003e\n\u003ctd\u003eReplaceable module\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003chr\u003e\n\u003ch3\u003eControlLogix Backplane ControlNet Scheduling Architecture\u003c\/h3\u003e\n\u003cp\u003eThe 1756-CNB\/B executes ControlNet communication through a deterministic scheduling engine integrated into the ControlLogix backplane. Cyclic data exchange is synchronized with controller task execution, enabling predictable frame delivery across a single-channel ControlNet segment.\u003c\/p\u003e\n\u003cp\u003eThe module supports both scheduled and unscheduled messaging, with network bandwidth allocation managed through ControlNet media access control mechanisms. Unlike redundant CN2R architecture, the CNB\/B operates on a single communication path without dual-channel fault tolerance, resulting in a simplified network topology with fixed node addressing up to 99 devices.\u003c\/p\u003e\n\u003cp\u003eUSB service access operates independently from cyclic network traffic and is used for configuration and diagnostic-level communication without affecting scheduled data exchanges.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eFrequently Asked Questions (FAQ)\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Does the 1756-CNB\/B support hot-swapping in an active chassis?\u003c\/strong\u003e\u003cbr\u003eA: Yes. The module supports removal and insertion under power. Reinitialization is handled via ControlLogix backplane rescan and module registration.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: How many ControlNet nodes can be configured?\u003c\/strong\u003e\u003cbr\u003eA: The module supports up to 99 nodes, constrained by ControlNet scheduling bandwidth and backplane resource allocation.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Does the module provide redundancy?\u003c\/strong\u003e\u003cbr\u003eA: No. The CNB\/B operates on a single-channel ControlNet architecture without redundant media paths.\u003c\/p\u003e\n\u003chr\u003e\u003chr\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003cp\u003eInstall the module into any available ControlLogix chassis slot ensuring full engagement with the backplane connector to maintain deterministic communication timing. ControlNet coaxial cabling must maintain impedance continuity and proper shielding integrity along trunk and drop segments.\u003c\/p\u003e\n\u003cp\u003eRoute ControlNet communication cables separately from high-power conductors to minimize electromagnetic coupling effects. Shield grounding should be implemented using a single-point earth reference to avoid ground loop formation.\u003c\/p\u003e\n\u003cp\u003eVerify firmware compatibility between controller, chassis, and communication module prior to commissioning to ensure stable backplane synchronization and network scheduling alignment.\u003c\/p\u003e","brand":"Allen-Bradley","offers":[{"title":"Default Title","offer_id":43577365954650,"sku":"1756-CNB\/B","price":123.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0612\/4601\/3530\/files\/1756-CNBR1.jpg?v=1777530544","url":"https:\/\/www.plcmasters.com\/products\/allen-bradley-1756-cnb-b-controllogix-controlnet-communication-module","provider":"PLC Masters Ltd.","version":"1.0","type":"link"}