{"product_id":"allen-bradley-1756-cn2-b-controlnet-communication-module","title":"Allen-Bradley 1756-CN2\/B ControlNet Communication Module","description":"\u003ch1 class=\"PDq2pG_selectionAnchorContainer\"\u003eAllen-Bradley 1756-CN2\/B ControlNet Communication Module\u003cspan class=\"PDq2pG_selectionAnchor\"\u003e\u003c\/span\u003e\n\u003c\/h1\u003e\n\u003cp\u003eConfigured for deterministic scheduled data exchange in ControlNet networks within ControlLogix automation systems, the\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eAllen-Bradley 1756-CN2\/B\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003e(\u003cstrong\u003e1756-CN2\/B\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003ecommunication module) provides direct network-level execution of controller-to-device communication over a 5 Mbps ControlNet medium.\u003c\/p\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-CN2\/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\u003eWeight\u003c\/td\u003e\n\u003ctd\u003e0.29 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOperating Temp\u003c\/td\u003e\n\u003ctd\u003e0 deg C to +60 deg C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePower Consumption\u003c\/td\u003e\n\u003ctd\u003e~5.1 W (derived from 1.0 A @ 5.1 V DC backplane draw)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNetwork Type\u003c\/td\u003e\n\u003ctd\u003eControlNet deterministic scheduled network\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eData Rate\u003c\/td\u003e\n\u003ctd\u003e5 Mbps\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePorts\u003c\/td\u003e\n\u003ctd\u003e2 BNC coaxial connectors\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBackplane Current Draw\u003c\/td\u003e\n\u003ctd\u003e~1.0 A @ 5.1 V DC\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\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003eControlNet Deterministic Scheduling and Redundant Media Operation\u003c\/h3\u003e\n\u003cp\u003eThe 1756-CN2\/B implements scheduled communication cycles on the ControlNet media layer, enforcing time-slot based data transmission between nodes. The module maintains fixed network scan timing at 5 Mbps, reducing variability in controller-to-device data exchange.\u003c\/p\u003e\n\u003cp\u003eDual BNC interfaces support redundant coaxial media paths. Media redundancy operates through continuous signal monitoring and automatic path selection, maintaining network continuity under single-channel degradation conditions. LED diagnostics provide real-time status of network traffic, node synchronization, and module state within the ControlLogix chassis backplane.\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions (FAQ)\u003c\/h3\u003e\n\u003cp\u003eQ: Does the 1756-CN2\/B support hot-swap replacement in a powered ControlLogix chassis?\u003cbr\u003eA: The module supports Removal and Insertion Under Power (RIUP) when installed in a compatible ControlLogix chassis slot. Network resynchronization occurs after reinsertion.\u003c\/p\u003e\n\u003cp\u003eQ: What is the effect of backplane load on module operation?\u003cbr\u003eA: The module draws approximately 1.0 A at 5.1 V DC from the chassis backplane. Excessive cumulative backplane loading across modules may affect system power budgeting.\u003c\/p\u003e\n\u003cp\u003eQ: How does redundant media affect communication timing?\u003cbr\u003eA: Dual BNC channels operate in parallel monitoring mode. Only one active path is used per scheduled transmission cycle, with automatic failover when signal integrity thresholds are violated.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003cp\u003eThe module shall be installed in a dedicated ControlLogix chassis slot with all power removed or under RIUP-compliant conditions. Coaxial ControlNet cabling must be terminated with specified end-of-line resistors to maintain impedance matching across the network segment. Cable shielding must be bonded at designated grounding points to avoid differential noise injection.\u003c\/p\u003e\n\u003cp\u003eNode addressing and network scheduling must be configured using RSNetWorx for ControlNet prior to runtime operation. Physical routing of BNC cabling shall avoid high-frequency drive lines and power conductors to reduce electromagnetic coupling effects. Chassis grounding shall follow ControlLogix system grounding architecture.\u003c\/p\u003e","brand":"Allen-Bradley","offers":[{"title":"Default Title","offer_id":43572473430106,"sku":"1756-CN2\/B","price":123.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0612\/4601\/3530\/files\/1756-CN21.jpg?v=1782791018","url":"https:\/\/www.plcmasters.com\/products\/allen-bradley-1756-cn2-b-controlnet-communication-module","provider":"PLC Masters Ltd.","version":"1.0","type":"link"}