{"product_id":"allen-bradley-1756-cn2r-d-controllogix-controlnet-redundant-communication-module","title":"Allen-Bradley 1756-CN2R\/D ControlLogix ControlNet Redundant Communication Module","description":"\u003ch1 class=\"PDq2pG_selectionAnchorContainer\"\u003eAllen-Bradley 1756-CN2R\/D ControlLogix ControlNet Redundant Communication Module\u003cspan class=\"PDq2pG_selectionAnchor\"\u003e\u003c\/span\u003e\n\u003c\/h1\u003e\n\u003cp\u003eConfigured for dual-channel ControlNet redundant network execution in ControlLogix backplane architectures, the\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eAllen-Bradley 1756-CN2R\/D\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003e(\u003cstrong\u003e1756-CN2R\/D\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eControlNet redundant communication module) provides direct physical and protocol-level routing of deterministic network frames across A\/B media paths within industrial automation controller systems. The module maintains synchronized multi-path data transmission for up to 100 simultaneous ControlNet connections through backplane-managed scheduling.\u003c\/p\u003e\n\u003cp\u003eManufactured within 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 platform family, the unit integrates EtherNet\/IP deterministic networks and ControlNet scheduling logic at the backplane interface layer to maintain continuous communication flow during redundancy operation.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eSuffix Breakdown \u0026amp; Model Matrix\u003c\/h3\u003e\n\u003cp\u003eSingle catalog configuration. No functional sub-variants defined beyond\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003e1756-CN2R\/D\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003erevision level within ControlLogix ControlNet redundant communication module series.\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-CN2R\/D\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\u003eNetwork Type\u003c\/td\u003e\n\u003ctd\u003eControlNet redundant A\/B channels\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eConnections\u003c\/td\u003e\n\u003ctd\u003eUp to 100 simultaneous connections\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eIsolation\u003c\/td\u003e\n\u003ctd\u003e30 V continuous basic insulation (A\/B to backplane and inter-channel paths)\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\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003chr\u003e\n\u003ch3\u003eControlLogix Backplane Deterministic Network Execution\u003c\/h3\u003e\n\u003cp\u003eThe 1756-CN2R\/D executes ControlNet scheduling through ControlLogix backplane arbitration, where cyclic data packets are aligned with deterministic scan intervals. Redundant A\/B channel operation is maintained at the media interface layer, allowing continuous propagation of network frames without application-layer intervention.\u003c\/p\u003e\n\u003cp\u003eEtherNet\/IP deterministic networks are coordinated through backplane bus communication scheduling, ensuring predictable data delivery timing between controller tasks and distributed I\/O nodes. The redundancy logic operates independently of controller program execution, maintaining continuous synchronization across both ControlNet paths.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eFrequently Asked Questions (FAQ)\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Does the 1756-CN2R\/D support hot-swap operation in ControlLogix chassis?\u003c\/strong\u003e\u003cbr\u003eA: Yes. The module supports hot insertion and removal, provided the chassis backplane reinitialization sequence is completed and configuration is retained in controller memory.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: How is redundancy handled between ControlNet A and B channels?\u003c\/strong\u003e\u003cbr\u003eA: Both channels operate in parallel with synchronized transmission. Redundancy is maintained at the network interface layer, with no galvanic isolation between A and B paths.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: What limits the number of simultaneous ControlNet connections?\u003c\/strong\u003e\u003cbr\u003eA: The module supports up to 100 connections, constrained by backplane bandwidth allocation and ControlNet scheduling capacity.\u003c\/p\u003e\n\u003chr\u003e\u003chr\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003cp\u003eInstall the module into a compatible ControlLogix chassis slot ensuring full backplane connector engagement to maintain deterministic communication timing. ControlNet cabling must follow impedance-matched routing with continuous shielding integrity across trunk and drop segments.\u003c\/p\u003e\n\u003cp\u003eMaintain physical separation between ControlNet media and high-frequency power conductors to reduce electromagnetic coupling. Shield termination should be implemented at a single-point earth reference to avoid ground loop formation across redundant A\/B channels.\u003c\/p\u003e\n\u003cp\u003eVerify firmware compatibility between controller, chassis, and communication module prior to commissioning to ensure consistent backplane synchronization and network scheduling alignment.\u003c\/p\u003e","brand":"Allen-Bradley","offers":[{"title":"Default Title","offer_id":43576252694618,"sku":"1756-CN2R\/D","price":123.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0612\/4601\/3530\/files\/1756-CN2RB.jpg?v=1782872883","url":"https:\/\/www.plcmasters.com\/products\/allen-bradley-1756-cn2r-d-controllogix-controlnet-redundant-communication-module","provider":"PLC Masters Ltd.","version":"1.0","type":"link"}