{"product_id":"allen-bradley-1756-irt8i-a-controllogix-rtd-thermocouple-input-module","title":"Allen-Bradley 1756-IRT8I\/A ControlLogix RTD\/Thermocouple Input Module","description":"\u003ch1 class=\"PDq2pG_selectionAnchorContainer\"\u003eAllen-Bradley 1756-IRT8I\/A ControlLogix RTD\/Thermocouple Input 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-IRT8I\/A\u003c\/strong\u003e, also cataloged as the\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003e1756-IRT8I\/A\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eRTD\/thermocouple analog input module, operates as a dedicated hardware component for temperature signal acquisition within ControlLogix backplane I\/O systems. Configured for RTD and thermocouple conversion in ControlLogix networks, the\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eAllen-Bradley 1756-IRT8I\/A (1756-IRT8I\/A temperature input module)\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eprovides direct electrical measurement of resistance and millivolt-level sensor outputs across 8 individually isolated channels.\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-based I\/O platform\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eIRT8\u003c\/strong\u003e: 8-channel RTD \/ thermocouple input structure\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eI\u003c\/strong\u003e: Individually isolated input architecture\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\/A\u003c\/strong\u003e: Hardware revision identifier\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eNo additional variant segmentation 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-IRT8I\/A\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\u003e4.6 W (backplane)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNumber of Inputs\u003c\/td\u003e\n\u003ctd\u003e8 isolated temperature input channels\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSignal Types\u003c\/td\u003e\n\u003ctd\u003eRTD (2-, 3-, 4-wire), Thermocouples (J, K, T, E, R, S, B, N)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInput Resistance Range\u003c\/td\u003e\n\u003ctd\u003e1 to 500 Ohms \/ 2 to 1000 Ohms \/ 4 to 2000 Ohms \/ 8 to 400 Ohms\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003emV Input Range\u003c\/td\u003e\n\u003ctd\u003e-100 to 100 mV\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eResolution\u003c\/td\u003e\n\u003ctd\u003e15 bits + sign\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAccuracy\u003c\/td\u003e\n\u003ctd\u003e±0.1% full scale\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCold Junction Compensation\u003c\/td\u003e\n\u003ctd\u003eBuilt-in (2 sensors)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eIsolation\u003c\/td\u003e\n\u003ctd\u003eChannel-to-channel isolation\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eContinuous Isolation Voltage\u003c\/td\u003e\n\u003ctd\u003e250 V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBackplane Current Draw\u003c\/td\u003e\n\u003ctd\u003e~200 mA at 5.1 VDC\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e24 VDC Current Draw\u003c\/td\u003e\n\u003ctd\u003e~150 mA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eThermal Dissipation\u003c\/td\u003e\n\u003ctd\u003e15.7 BTU\/h\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eConversion Method\u003c\/td\u003e\n\u003ctd\u003eSigma-Delta\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMinimum Scan Time\u003c\/td\u003e\n\u003ctd\u003e1 ms\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eConnector Type\u003c\/td\u003e\n\u003ctd\u003e36-pin RTB or 1492 IFM interface module\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCertifications\u003c\/td\u003e\n\u003ctd\u003eUL, CE, CSA, hazardous location approvals\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003chr\u003e\n\u003ch3\u003eControlLogix Backplane Deterministic Temperature Acquisition Behavior\u003c\/h3\u003e\n\u003cp\u003eThe 1756-IRT8I\/A executes sigma-delta conversion per channel prior to ControlLogix backplane data publication. Temperature values derived from RTD resistance or thermocouple millivolt input are normalized into engineering units within module firmware before cyclic transfer to controller memory.\u003c\/p\u003e\n\u003cp\u003eChannel-to-channel isolation maintains electrical separation between mixed sensor types during simultaneous sampling. Cold junction compensation is executed internally using dual reference sensors, ensuring thermocouple EMF correction independent of terminal block temperature variation.\u003c\/p\u003e\n\u003cp\u003eBackplane scan timing is governed by chassis slot configuration and controller task rate, with minimum module input scan capability down to 1 ms under optimized configuration.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eFrequently Asked Questions (FAQ)\u003c\/h3\u003e\n\u003cp\u003eQ: Can RTD and thermocouple inputs be mixed on the same module?\u003cbr\u003eA: Yes. Each of the 8 channels supports independent configuration for RTD or thermocouple input types, allowing mixed sensor deployment within a single module.\u003c\/p\u003e\n\u003cp\u003eQ: How does channel isolation affect temperature measurement stability?\u003cbr\u003eA: Channel-to-channel isolation prevents electrical interaction between sensor loops, reducing measurement drift caused by ground potential differences or shared return paths.\u003c\/p\u003e\n\u003cp\u003eQ: What is the role of cold junction compensation in this module?\u003cbr\u003eA: The module uses two internal CJC sensors to correct thermocouple junction voltage, compensating for terminal temperature variations at the RTB interface before digitization.\u003c\/p\u003e\n\u003chr\u003e\u003chr\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003cul class=\"list-paddingleft-2\"\u003e\n\u003cli\u003e\n\u003cp\u003eInstall module into a compatible 1756 ControlLogix chassis slot with system power removed or per approved insertion procedure\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eEnsure RTB or 1492 IFM connector is fully seated prior to energizing field wiring\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eUse shielded twisted pair wiring for thermocouple inputs; terminate shield at one end only\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMaintain separation between low-level millivolt sensor wiring and high-voltage conductors to reduce induced noise\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eVerify correct sensor type configuration (RTD or thermocouple) before loop energization\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eAvoid exceeding specified input range (resistance or mV) during commissioning to prevent conversion errors\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Allen-Bradley","offers":[{"title":"Default Title","offer_id":43602602033242,"sku":"1756-IRT8I\/A","price":123.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0612\/4601\/3530\/files\/1756-IRT8IA2.jpg?v=1783319771","url":"https:\/\/www.plcmasters.com\/products\/allen-bradley-1756-irt8i-a-controllogix-rtd-thermocouple-input-module","provider":"PLC Masters Ltd.","version":"1.0","type":"link"}