{"product_id":"allen-bradley-1756-cnb-e-controllogix-controlnet-communication-module","title":"Allen-Bradley 1756-CNB\/E ControlLogix ControlNet Communication Module","description":"\u003ch1 class=\"PDq2pG_selectionAnchorContainer\"\u003eAllen-Bradley 1756-CNB\/E ControlLogix ControlNet Communication Module\u003cspan class=\"PDq2pG_selectionAnchor\"\u003e\u003c\/span\u003e\n\u003c\/h1\u003e\n\u003cp\u003eThe\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eAllen-Bradley 1756-CNB\/E\u003c\/strong\u003e, also cataloged as the\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003e1756-CNB\/E\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eControlNet communication module, operates as a dedicated interface component for deterministic ControlNet frame scheduling between ControlLogix backplane controllers and a single-channel ControlNet network within a ControlLogix chassis architecture. Configured for both scheduled and unscheduled communication handling, the\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003e1756-CNB\/E\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eprovides direct physical and protocol-level execution of ControlNet data transfer at the network interface layer.\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 system, the module maps controller task execution to ControlNet media timing, enabling synchronized cyclic data exchange between controllers and distributed nodes under a fixed 5 Mbps communication structure.\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\/E\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\u003e0.2 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDimensions\u003c\/td\u003e\n\u003ctd\u003e3.8 cm x 15.2 cm x 14.0 cm\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\u003eControlNet Deterministic Scheduling and Backplane Execution\u003c\/h3\u003e\n\u003cp\u003eThe 1756-CNB\/E executes ControlNet communication through deterministic scheduling integrated into the ControlLogix backplane architecture. Cyclic data transfer is synchronized with controller scan cycles, ensuring predictable timing of input and output updates across the network.\u003c\/p\u003e\n\u003cp\u003eSingle-channel ControlNet topology is used without redundant media paths. Network bandwidth allocation is managed via scheduled time slots, where each node is assigned deterministic transmission windows under a fixed 5 Mbps communication rate.\u003c\/p\u003e\n\u003cp\u003eUSB service access operates independently of cyclic traffic and is used for configuration and diagnostic-level communication without impacting scheduled data flow.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eFrequently Asked Questions (FAQ)\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Does the 1756-CNB\/E support hot-swapping in a live system?\u003c\/strong\u003e\u003cbr\u003eA: Yes. The module supports hot insertion and removal. Reinitialization occurs through chassis backplane rescan and configuration reload.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: What is the maximum number of ControlNet connections?\u003c\/strong\u003e\u003cbr\u003eA: The module supports up to 99 connections, constrained by ControlNet scheduling bandwidth and backplane communication resources.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Does this module support redundant ControlNet paths?\u003c\/strong\u003e\u003cbr\u003eA: No. The CNB\/E operates on a single-channel ControlNet architecture without redundancy support.\u003c\/p\u003e\n\u003chr\u003e\u003chr\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003cp\u003eInstall the module into any compatible ControlLogix chassis slot ensuring full engagement with the backplane connector. ControlNet coaxial cabling must maintain impedance matching and continuous shielding integrity across trunk and drop segments.\u003c\/p\u003e\n\u003cp\u003eRoute communication cables away from high-current conductors to reduce electromagnetic coupling effects. Shield grounding shall be implemented using a single-point earth reference to avoid loop current formation in the network.\u003c\/p\u003e\n\u003cp\u003eVerify firmware compatibility between controller, chassis, and communication module prior to commissioning to ensure correct backplane synchronization and deterministic scheduling behavior.\u003c\/p\u003e","brand":"Allen-Bradley","offers":[{"title":"Default Title","offer_id":43577382371418,"sku":"1756-CNB\/E","price":123.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0612\/4601\/3530\/files\/1756-CNBE2.jpg?v=1782887218","url":"https:\/\/www.plcmasters.com\/products\/allen-bradley-1756-cnb-e-controllogix-controlnet-communication-module","provider":"PLC Masters Ltd.","version":"1.0","type":"link"}