{"product_id":"allen-bradley-1756-cnbr-e-controlnet-redundant-communication-module","title":"Allen-Bradley 1756-CNBR\/E ControlNet Redundant Communication Module","description":"\u003ch1 class=\"PDq2pG_selectionAnchorContainer\"\u003eAllen-Bradley 1756-CNBR\/E ControlNet Redundant 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-CNBR\/E\u003c\/strong\u003e, also cataloged as the\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003e1756-CNBR\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eControlNet redundant communication module, serves as the primary communication interface for dual-channel ControlNet networking across ControlLogix platforms. It provides direct physical layer execution for redundant A\/B ControlNet data paths, supporting deterministic scheduled and unscheduled message exchange between controllers and distributed nodes.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eSuffix Breakdown \u0026amp; Model Matrix\u003c\/h3\u003e\n\u003cul class=\"list-paddingleft-2\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e1756\u003c\/strong\u003e: ControlLogix chassis platform identifier\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eCNBR\u003c\/strong\u003e: ControlNet redundant bridge communication module designation\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\/E\u003c\/strong\u003e: Hardware revision level indicator within the CNBR series\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eNo additional functional segmentation is defined beyond platform family and revision suffix.\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-CNBR\/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\u003eWeight\u003c\/td\u003e\n\u003ctd\u003e1.00 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePower Consumption\u003c\/td\u003e\n\u003ctd\u003e5.5 W (max dissipation)\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\u003eMax Connections\u003c\/td\u003e\n\u003ctd\u003eUp to 100 simultaneous connections\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBackplane Current (5.1 VDC)\u003c\/td\u003e\n\u003ctd\u003e970 mA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBackplane Current (24 VDC)\u003c\/td\u003e\n\u003ctd\u003e1.7 mA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eIsolation Voltage\u003c\/td\u003e\n\u003ctd\u003e30 V continuous basic insulation\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCommunication Ports\u003c\/td\u003e\n\u003ctd\u003eTwo ControlNet ports\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEMC 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\u003eChassis Location\u003c\/td\u003e\n\u003ctd\u003eControlLogix 1756 backplane slot\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEnclosure Type\u003c\/td\u003e\n\u003ctd\u003eOpen type\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003chr\u003e\n\u003ch3\u003eRedundant ControlNet Channel Execution and Backplane Behavior\u003c\/h3\u003e\n\u003cp\u003eThe module implements dual independent ControlNet channels (A\/B) for fault-tolerant deterministic communication. Both channels operate in parallel with synchronized network scheduling to maintain continuity of scheduled and unscheduled data transfer.\u003c\/p\u003e\n\u003cp\u003eBackplane integration is executed through the 1756 chassis communication bus, with module-level arbitration managing connection instances up to 100 simultaneous links. Channel monitoring logic maintains link status and triggers failover behavior at the network interface layer without requiring controller intervention.\u003c\/p\u003e\n\u003cp\u003eElectromagnetic immunity design supports operation under defined industrial field strengths, ensuring signal integrity across redundant coaxial ControlNet media paths.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eFrequently Asked Questions (FAQ)\u003c\/h3\u003e\n\u003cp\u003eQ: Does the 1756-CNBR\/E support simultaneous operation of both ControlNet channels?\u003cbr\u003eA: Yes. Both A and B channels operate in parallel, with synchronization handled internally for redundancy and continuous communication.\u003c\/p\u003e\n\u003cp\u003eQ: What happens if one ControlNet channel fails?\u003cbr\u003eA: The module continues operation on the remaining channel while reporting channel fault status through diagnostic registers and controller feedback.\u003c\/p\u003e\n\u003cp\u003eQ: Is the module hot-swappable during chassis operation?\u003cbr\u003eA: Yes. It supports hot replacement within a ControlLogix chassis, but communication re-establishment depends on network rescheduling and connection recovery.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003cp\u003eThe module shall be installed in a compatible ControlLogix 1756 chassis slot with controlled insertion into the backplane connector. Power cycling is recommended unless hot-swap procedures are explicitly supported by system configuration.\u003c\/p\u003e\n\u003cp\u003eControlNet A\/B coaxial cables must be routed with physical separation to reduce correlated interference risk. Proper 75 ohm termination must be verified at network endpoints to maintain signal integrity.\u003c\/p\u003e\n\u003cp\u003eShielding shall be grounded at a single-point earth reference to prevent loop currents across redundant paths. All cabling must comply with ControlNet topology requirements including trunk\/drop length constraints and connector torque specifications defined by system standards.\u003c\/p\u003e","brand":"Allen-Bradley","offers":[{"title":"Default Title","offer_id":43577402130522,"sku":"1756-CNBR\/E","price":123.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0612\/4601\/3530\/files\/1756-CNBRB1.jpg?v=1782887913","url":"https:\/\/www.plcmasters.com\/products\/allen-bradley-1756-cnbr-e-controlnet-redundant-communication-module","provider":"PLC Masters Ltd.","version":"1.0","type":"link"}