{"product_id":"allen-bradley-1756-cnbr-b-controlnet-redundant-communication-module","title":"Allen-Bradley 1756-CNBR\/B ControlNet Redundant Communication Module","description":"\u003ch1 class=\"PDq2pG_selectionAnchorContainer\"\u003eAllen-Bradley 1756-CNBR\/B 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\/B\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, operates as a dedicated hardware interface for dual-channel ControlNet data exchange within ControlLogix chassis networks. It provides physical layer execution for redundant A\/B ControlNet communication paths, supporting deterministic scheduled and unscheduled message transfer across distributed controller 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 platform chassis family identifier\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eCNBR\u003c\/strong\u003e: ControlNet Redundant communication bridge module designation\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\/B\u003c\/strong\u003e: Hardware revision indicator (revision-specific implementation level)\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eNo additional functional segmentation beyond revision and platform coding is defined in the provided dataset.\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\/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\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\u003eIsolation\u003c\/td\u003e\n\u003ctd\u003e30 V continuous, basic insulation (A\/B to backplane, channel-to-channel, USB isolation paths)\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 defined test profiles)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCommunication Behavior\u003c\/td\u003e\n\u003ctd\u003eDeterministic scheduled \/ unscheduled ControlNet transfer\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eChassis Interface\u003c\/td\u003e\n\u003ctd\u003eControlLogix backplane communication\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003chr\u003e\n\u003ch3\u003eControlNet Redundant Channel Architecture and Backplane Integration\u003c\/h3\u003e\n\u003cp\u003eThe module implements dual independent ControlNet communication paths (A\/B) for fault-tolerant operation. Channel switching and synchronization are handled at the network interface layer while maintaining backplane-level integration with ControlLogix processors.\u003c\/p\u003e\n\u003cp\u003eBackplane communication is executed through the 1756 chassis bus, with deterministic data exchange timing aligned to ControlNet scheduling cycles. The module participates in system-wide I\/O and controller messaging through configured connection instances.\u003c\/p\u003e\n\u003cp\u003eFirmware execution and network stack behavior remain aligned with ControlLogix platform compatibility requirements, including revision-dependent Studio 5000 configuration support.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eFrequently Asked Questions (FAQ)\u003c\/h3\u003e\n\u003cp\u003eQ: Can the 1756-CNBR\/B operate in a single-channel mode if one ControlNet path fails?\u003cbr\u003eA: Yes. The module maintains operation using the remaining ControlNet channel, while fault status is reported at the chassis and network diagnostics level.\u003c\/p\u003e\n\u003cp\u003eQ: Is the module hot-swappable within a running ControlLogix chassis?\u003cbr\u003eA: Yes. The module supports hot replacement, but network re-establishment depends on connection reallocation and scheduled ControlNet updates.\u003c\/p\u003e\n\u003cp\u003eQ: Does the redundant A\/B design include full electrical isolation between channels?\u003cbr\u003eA: No. Only basic insulation is implemented; there is no full galvanic isolation between ControlNet A and B paths.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003cp\u003eThe module must be installed in a compatible ControlLogix 1756 chassis slot with backplane power removed or under controlled hot-swap procedure. ControlNet coaxial cabling should maintain impedance consistency and proper termination at both network ends.\u003c\/p\u003e\n\u003cp\u003eShielding must be grounded at a single defined earth reference point to prevent ground loop currents across redundant channels. Cable routing for A\/B networks should be physically separated to reduce correlated failure risk.\u003c\/p\u003e\n\u003cp\u003eUSB service access (if used for diagnostics) must be isolated from ControlNet trunk cabling to avoid EMI coupling. Slot configuration must match Studio 5000 project mapping before network activation.\u003c\/p\u003e","brand":"Allen-Bradley","offers":[{"title":"Default Title","offer_id":43577396985946,"sku":"1756-CNBR\/B","price":123.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0612\/4601\/3530\/files\/1756-CNBRB2.jpg?v=1782887913","url":"https:\/\/www.plcmasters.com\/products\/allen-bradley-1756-cnbr-b-controlnet-redundant-communication-module","provider":"PLC Masters Ltd.","version":"1.0","type":"link"}