{"product_id":"allen-bradley-1756-cjc-controllogix-cold-junction-compensation-module","title":"Allen-Bradley 1756-CJC ControlLogix Cold Junction Compensation Module","description":"\u003ch1 class=\"PDq2pG_selectionAnchorContainer\"\u003eAllen-Bradley 1756-CJC ControlLogix Cold Junction Compensation Module\u003cspan class=\"PDq2pG_selectionAnchor\"\u003e\u003c\/span\u003e\n\u003c\/h1\u003e\n\u003cp\u003eConfigured for cold junction temperature reference correction in thermocouple input processing within ControlLogix systems, the\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eAllen-Bradley 1756-CJC\u003c\/strong\u003e, also cataloged as the\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003e1756-CJC\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eCJC thermistor module, provides direct electrical temperature compensation for analog measurement accuracy in ControlLogix IRT8I and IT16 input configurations. The device supplies reference junction stabilization through backplane-powered sensing elements used by compatible thermocouple modules.\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-CJC\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\u003e0.03 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePower Consumption\u003c\/td\u003e\n\u003ctd\u003e6 W max @ 60 deg C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSensor Type\u003c\/td\u003e\n\u003ctd\u003eCold Junction Compensation (CJC) thermistor\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBackplane Current (5 V DC)\u003c\/td\u003e\n\u003ctd\u003e300 mA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBackplane Current (24 V DC)\u003c\/td\u003e\n\u003ctd\u003e6 mA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatible Modules\u003c\/td\u003e\n\u003ctd\u003e1756-IRT8I, 1756-IT16\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTerminal Blocks\u003c\/td\u003e\n\u003ctd\u003e1756-TBNH, 1756-TBSH\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003eBackplane Bus Communication and CJC Integration\u003c\/h3\u003e\n\u003cp\u003eWithin ControlLogix architecture, the 1756-CJC participates as a passive reference element for thermocouple linearization circuits. Temperature compensation values are sampled via backplane-assisted acquisition paths of the 1756-IRT8I or 1756-IT16 modules. The compensation function is applied at the module signal conditioning stage prior to A\/D conversion, ensuring junction voltage correction relative to chassis temperature drift. Backplane power distribution at 5 V DC supports thermistor excitation and reference stabilization.\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003eQ: Does the 1756-CJC perform signal conversion or only temperature reference sensing?\u003cbr\u003eA: The module provides only cold junction reference sensing. Signal conversion is handled by the associated 1756-IRT8I or 1756-IT16 input modules.\u003c\/p\u003e\n\u003cp\u003eQ: Can the 1756-CJC operate without backplane power?\u003cbr\u003eA: No. The thermistor network requires 5 V DC backplane supply for reference excitation and temperature measurement stability.\u003c\/p\u003e\n\u003cp\u003eQ: Is the module electrically isolated from thermocouple input channels?\u003cbr\u003eA: Isolation is defined at the input module level. The 1756-CJC itself functions as a passive sensing element without channel isolation circuitry.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003cp\u003eInstall the 1756-CJC in a ControlLogix chassis adjacent to compatible thermocouple input modules (1756-IRT8I or 1756-IT16). Ensure full engagement with the backplane connector to maintain reference continuity. Route thermocouple wiring separately from power conductors to minimize thermal and electrical interference. Maintain proper grounding of the chassis to stabilize reference junction potential. Do not apply external voltage to the CJC terminals; the element operates strictly under backplane-supplied excitation.\u003c\/p\u003e","brand":"Allen-Bradley","offers":[{"title":"Default Title","offer_id":43572453867610,"sku":"1756-CJC","price":123.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0612\/4601\/3530\/files\/1756-CJC2.jpg?v=1782790009","url":"https:\/\/www.plcmasters.com\/products\/allen-bradley-1756-cjc-controllogix-cold-junction-compensation-module","provider":"PLC Masters Ltd.","version":"1.0","type":"link"}