{"product_id":"mtl4081-mtl-low-level-signal-isolator-for-thermocouples","title":"MTL4081 MTL Low-Level Signal Isolator for Thermocouples","description":"\u003ch3\u003e\u003cb\u003eProduct Overview\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp\u003eThe \u003cb\u003e\u003cspan style=\"color: #e67e22;\"\u003eMTL4081\u003c\/span\u003e\u003c\/b\u003e is a single-channel millivolt and thermocouple isolator from the \u003cb\u003eMTL4000 Series\u003c\/b\u003e. It transfers low-level DC signals from hazardous areas to safe-area instruments.\u003c\/p\u003e\n\u003cp\u003eThe module provides electrical isolation between field signal sources and receiving equipment. It supports strain-gauge bridges and thermocouples with external cold-junction compensation.\u003c\/p\u003e\n\u003cp\u003eThe \u003cb\u003eMTL4081\u003c\/b\u003e accepts millivolt signals from certified hazardous-area circuits. It transfers the measured signal to a receiving instrument in the safe area. Its low signal drift supports stable measurement in industrial applications.\u003c\/p\u003e\n\u003cp\u003eTwo configuration switches simplify thermocouple fault handling. One switch enables or disables the safety drive. The second switch selects upscale or downscale operation after a thermocouple burnout or cable break.\u003c\/p\u003e\n\u003ch3\u003e\u003cb\u003eTechnical Specifications\u003c\/b\u003e\u003c\/h3\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cb\u003eParameter\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cb\u003eSpecification\u003c\/b\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBrand\u003c\/td\u003e\n\u003ctd\u003eMTL\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eModel\u003c\/td\u003e\n\u003ctd\u003e\u003cb\u003eMTL4081\u003c\/b\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSeries\u003c\/td\u003e\n\u003ctd\u003eMTL4000 Series\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eProduct Type\u003c\/td\u003e\n\u003ctd\u003eMillivolt \/ Thermocouple Isolator\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNumber of Channels\u003c\/td\u003e\n\u003ctd\u003e1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSignal Source\u003c\/td\u003e\n\u003ctd\u003eAny DC millivolt source\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInput Signal Range\u003c\/td\u003e\n\u003ctd\u003e0 to ±50 mV\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOverrange Capability\u003c\/td\u003e\n\u003ctd\u003eUp to ±55 mV\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOutput Signal Range\u003c\/td\u003e\n\u003ctd\u003e0 to ±50 mV\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOutput Resistance\u003c\/td\u003e\n\u003ctd\u003e60 Ω nominal\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransfer Accuracy\u003c\/td\u003e\n\u003ctd\u003eLinearity and repeatability below 0.05% of reading or ±5 µV, whichever is greater\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTemperature Drift\u003c\/td\u003e\n\u003ctd\u003eLess than 2 µV\/°C maximum\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eResponse Time\u003c\/td\u003e\n\u003ctd\u003eWithin 10% of final value in 150 µs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFrequency Response\u003c\/td\u003e\n\u003ctd\u003eDC to 4 kHz nominal\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePower Supply\u003c\/td\u003e\n\u003ctd\u003e20 to 35 V DC\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaximum Supply Current\u003c\/td\u003e\n\u003ctd\u003e26 mA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePower Dissipation\u003c\/td\u003e\n\u003ctd\u003e0.6 W typical at 24 V; 0.9 W at 35 V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eElectrical Isolation\u003c\/td\u003e\n\u003ctd\u003e250 V AC between safe-area and hazardous-area circuits\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePower Indicator\u003c\/td\u003e\n\u003ctd\u003eGreen LED\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eConfiguration\u003c\/td\u003e\n\u003ctd\u003eSafety drive enable\/disable and upscale\/downscale selection\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003e\u003cb\u003eCore Functions and Engineering Advantages\u003c\/b\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cb\u003eMillivolt Signal Isolation:\u003c\/b\u003e Transfers low-level DC signals between hazardous and safe areas.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eSingle-Channel Processing:\u003c\/b\u003e Handles one independent millivolt signal channel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eMeasurement Accuracy:\u003c\/b\u003e Provides less than 0.05% transfer linearity and repeatability, subject to the specified accuracy limit.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eLow Temperature Drift:\u003c\/b\u003e Limits drift to 2 µV\/°C maximum.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eFast Signal Response:\u003c\/b\u003e Reaches the specified response tolerance within 150 µs.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eThermocouple Fault Handling:\u003c\/b\u003e Supports configurable upscale or downscale safety drive.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eField Signal Compatibility:\u003c\/b\u003e Supports strain-gauge bridges and thermocouples with external cold-junction compensation.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eElectrical Separation:\u003c\/b\u003e Provides 250 V AC isolation between field and safe-area circuits.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cb\u003eTerminal Configuration\u003c\/b\u003e\u003c\/h3\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cb\u003eTerminal\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cb\u003eFunction\u003c\/b\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e5\u003c\/td\u003e\n\u003ctd\u003eTHC \/ EMF Input Positive (+)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e6\u003c\/td\u003e\n\u003ctd\u003eTHC \/ EMF Input Negative (-)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e9\u003c\/td\u003e\n\u003ctd\u003eOutput Positive (+)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e11\u003c\/td\u003e\n\u003ctd\u003eOutput Negative (-)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e13\u003c\/td\u003e\n\u003ctd\u003ePower Supply Negative (-)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e14\u003c\/td\u003e\n\u003ctd\u003ePower Supply Positive (+)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cb\u003eImportant Electrical Note:\u003c\/b\u003e Output negative at terminal 11 connects to supply negative at terminal 13 through two series diodes. Check this circuit arrangement before connecting external equipment.\u003c\/p\u003e\n\u003ch3\u003e\u003cb\u003eInstallation Guidelines\u003c\/b\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eInstall the \u003cb\u003eMTL4081\u003c\/b\u003e in a compatible MTL system mounting arrangement.\u003c\/li\u003e\n\u003cli\u003eCheck the module identification and terminal markings before installation.\u003c\/li\u003e\n\u003cli\u003eConnect the millivolt source to terminals 5 and 6.\u003c\/li\u003e\n\u003cli\u003eConnect the receiving instrument to output terminals 9 and 11.\u003c\/li\u003e\n\u003cli\u003eConnect the DC supply to terminals 14 and 13.\u003c\/li\u003e\n\u003cli\u003eMaintain correct polarity throughout the signal and power circuits.\u003c\/li\u003e\n\u003cli\u003eUse suitable certified field devices and wiring for hazardous-area installations.\u003c\/li\u003e\n\u003cli\u003eFollow the applicable intrinsic safety control drawings and installation requirements.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cb\u003eCommissioning and Maintenance\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp\u003eCommissioning should include supply, signal, polarity, and isolation checks. Follow these practical steps:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cb\u003ePower Verification:\u003c\/b\u003e Confirm that the supply remains within 20–35 V DC.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eLED Inspection:\u003c\/b\u003e Check the green LED for power indication.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eInput Verification:\u003c\/b\u003e Apply a known millivolt signal within the specified range.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eOutput Verification:\u003c\/b\u003e Compare the receiving instrument reading with the applied input.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eFault Simulation:\u003c\/b\u003e Check the configured safety drive response under an approved test procedure.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eSwitch Inspection:\u003c\/b\u003e Confirm the required safety drive and upscale\/downscale settings.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eRoutine Maintenance:\u003c\/b\u003e Inspect terminals, wiring, and mounting conditions during scheduled maintenance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eAlways isolate power before wiring changes. Use approved test equipment for hazardous-area maintenance. Do not perform live wiring operations unless the installation procedure explicitly permits them.\u003c\/p\u003e\n\u003ch3\u003e\u003cb\u003eCompatibility and Application Areas\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp\u003eThe \u003cb\u003eMTL4081\u003c\/b\u003e suits industrial measurement systems that require isolated low-level DC signal transmission.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eStrain-gauge bridge measurement systems.\u003c\/li\u003e\n\u003cli\u003eThermocouple measurement circuits with external cold-junction compensation.\u003c\/li\u003e\n\u003cli\u003eHazardous-area process instrumentation.\u003c\/li\u003e\n\u003cli\u003eIndustrial temperature monitoring systems.\u003c\/li\u003e\n\u003cli\u003eLow-level voltage measurement applications.\u003c\/li\u003e\n\u003cli\u003eProcess control and data acquisition systems.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cb\u003eCompatibility Considerations:\u003c\/b\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eThe field source must provide a compatible DC millivolt signal.\u003c\/li\u003e\n\u003cli\u003eThe receiving instrument must accept the specified millivolt output.\u003c\/li\u003e\n\u003cli\u003eCheck the input impedance and wiring arrangement of the receiving device.\u003c\/li\u003e\n\u003cli\u003eVerify the external cold-junction compensation arrangement for thermocouple applications.\u003c\/li\u003e\n\u003cli\u003eConfirm the system supply and intrinsic safety requirements before installation.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cb\u003eHazardous-Area Safety and Certification Information\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp\u003eThe manufacturer specifies the following hazardous-area application conditions:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cb\u003eATEX \/ Intrinsic Safety Application:\u003c\/b\u003e Zone 0, IIC, T4–T6, when used with suitable certification.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eNorth American Application:\u003c\/b\u003e Division 1, Group A hazardous location, subject to the applicable system certification.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eIsolation Rating:\u003c\/b\u003e 250 V AC between safe-area and hazardous-area circuits.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cb\u003eIntrinsic Safety Parameters – Terminals 5 and 6:\u003c\/b\u003e\u003c\/p\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cb\u003eParameter\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cb\u003eValue\u003c\/b\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eUmax out\u003c\/td\u003e\n\u003ctd\u003e1.0 V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eImax out\u003c\/td\u003e\n\u003ctd\u003e47.8 mA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePmax out\u003c\/td\u003e\n\u003ctd\u003e0.012 W\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNon-energy-storing Apparatus Limits\u003c\/td\u003e\n\u003ctd\u003e≤1.2 V, ≤0.1 A, ≤20 µJ and ≤25 mW\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaximum IS Loop Open-Circuit Voltage\u003c\/td\u003e\n\u003ctd\u003e28 V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003eThe manufacturer states that the input circuit can connect to an intrinsically safe loop without additional certification when the open-circuit voltage does not exceed 28 V. Verify the complete loop parameters before installation.\u003c\/p\u003e\n\u003cp\u003eAlways consult the applicable MTL common specifications, cable parameters, certificates, and control drawings. The final approval depends on the complete installation and associated equipment.\u003c\/p\u003e\n\u003ch3\u003e\u003cb\u003ePackaging and Delivery\u003c\/b\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e1 × \u003cb\u003eMTL4081 Millivolt \/ Thermocouple Isolator\u003c\/b\u003e\n\u003c\/li\u003e\n\u003cli\u003eProtective packaging for transportation.\u003c\/li\u003e\n\u003cli\u003eProduct identification and order verification.\u003c\/li\u003e\n\u003cli\u003eTechnical documentation, subject to availability.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eContact Global PLC Spare HUB to confirm the exact supply configuration and documentation requirements before ordering.\u003c\/p\u003e\n\u003ch3\u003e\u003cb\u003eGlobal PLC Spare HUB's Insight\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp\u003eThe \u003cb\u003eMTL4081\u003c\/b\u003e addresses a specific instrumentation requirement: isolated transmission of low-level millivolt signals from hazardous areas.\u003c\/p\u003e\n\u003cp\u003eIts 0.05% transfer linearity and repeatability specification supports precision measurement applications. The maximum 2 µV\/°C temperature drift also helps maintain signal stability.\u003c\/p\u003e\n\u003cp\u003eEngineers should pay particular attention to thermocouple fault handling. The two configuration switches determine the safety drive and fault-direction behavior. Incorrect settings can produce an unexpected receiving instrument response during sensor failure.\u003c\/p\u003e\n\u003cp\u003eFor strain-gauge applications, engineers should verify bridge compatibility and signal conditioning requirements. For thermocouple applications, they should confirm external cold-junction compensation. These checks help prevent measurement errors during commissioning.\u003c\/p\u003e\n\u003cp\u003eWhen replacing or selecting an isolator, compare the signal range, terminal arrangement, isolation requirements, and intrinsic safety parameters. Matching the model number alone does not guarantee system compatibility.\u003c\/p\u003e\n\u003ch3\u003e\u003cb\u003eFrequently Asked Questions (FAQ)\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cb\u003e1. What is the main function of the MTL4081?\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003eThe \u003cb\u003eMTL4081\u003c\/b\u003e isolates low-level DC millivolt signals from hazardous areas. It transfers these signals to safe-area receiving instruments. It supports strain-gauge bridges and thermocouples with external cold-junction compensation.\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003e2. Can the MTL4081 process standard thermocouple signals directly?\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003eThe module supports thermocouple applications with external cold-junction compensation. Engineers must provide a suitable compensation arrangement. Do not assume the module includes internal cold-junction compensation.\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003e3. How should engineers configure the thermocouple burnout function?\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003eUse the two top-mounted switches for fault-response configuration. One enables or disables the safety drive. The other selects upscale or downscale operation. Engineers should follow the process safety requirements and verify the response during commissioning.\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003e4. What should engineers check when replacing an existing MTL4081?\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003eFirst, verify the complete model number and terminal configuration. Then compare the signal range, power supply, isolation, and intrinsic safety parameters. Also check the receiving instrument and thermocouple compensation arrangement. Confirm mechanical and system compatibility before replacement.\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003e5. How can buyers select the correct MTL4081 module?\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003eConfirm that the application requires a single-channel millivolt isolator. Check the ±50 mV operating range and ±55 mV overrange capability. Verify the 20–35 V DC supply requirement. Finally, review hazardous-area approvals and fault-response settings. Contact Global PLC Spare HUB for model verification and quotation support.\u003c\/p\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0722\/7863\/8774\/files\/MTL4081_2.png?v=1793847530\" alt=\"\"\u003e\u003c\/p\u003e","brand":"MTL","offers":[{"title":"Default Title","offer_id":45014021144758,"sku":"MTL4081","price":142.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0722\/7863\/8774\/files\/MTL4081_3d70b6e0-be7f-4840-98ee-30dc800a954c.jpg?v=1793850431","url":"https:\/\/www.plcsparehub.com\/products\/mtl4081-mtl-low-level-signal-isolator-for-thermocouples","provider":"Global PLC Spare Hub","version":"1.0","type":"link"}