MTL4573 Isolated Temperature Signal Converter THC RTD Hazardous Area

Advanced Thermal Signal Conditioning

The MTL4573 is a high-performance, single-channel temperature converter designed to interface hazardous area sensors with safe area control systems. This module provides galvanic isolation and converts low-level DC signals from thermocouples (THC) or resistance temperature detectors (RTD) into a robust 4-20mA output. The MTL4573 features comprehensive software-driven configuration, allowing engineers to define linearization, ranging, and tagging via the PCS45 software suite. Its integrated Cold Junction Compensation (CJC) and support for GOST-standard sensors make it a versatile global solution.

Technical Specification Matrix

• Brand: MTL Instruments / Eaton
• Model: MTL4573
• Series: MTL4500 Isolator Range
• Hazardous Area Location: Zone 0, IIC; Class I, Div 1, Groups A-D
• Thermocouple Support: Types J, K, T, E, R, S, B, N, XK (Min Span: 3mV)
• RTD Support: Pt100, Pt500, Pt1000 (2, 3, or 4-wire configurations)
• Millivolt Input Range: -75 to +75mV
• Output Signal: 4 to 20mA nominal (600 Ohm maximum load)
• Calibration Accuracy: +/- 15uV (mV/THC) / +/- 80mOhm (Pt100) / +/- 11uA (Output)
• Response Time: 500 ms (Typical)
• Cold Junction Compensation: Selectable ON/OFF (Error <= 1.0 C)
• Common Mode Rejection: 120dB for 240V @ 50/60Hz
• Power Dissipation: 1.2W @ 24V DC

Global PLC Spare HUB's Insight

The MTL4573 is a standout in the MTL4500 series due to its specialized Early Burnout Detection (EBD). This feature allows maintenance teams to identify degrading thermocouples before a complete failure occurs, preventing unexpected process trips. Our engineering team notes that the 4-wire RTD support on the MTL4573 effectively eliminates lead resistance errors, making it superior for high-precision laboratory and pharmaceutical applications where thermal gradients must be strictly managed.

Target Systems and Applications

• DCS/ESD Integration: Converting field temperature data for Honeywell, Emerson, or Yokogawa systems.
• Cryogenic Storage: Utilizing Pt1000 RTDs for ultra-low temperature monitoring in Zone 0.
• Furnace Control: High-accuracy thermocouple monitoring (Types R/S) for metal processing.
• Hazardous Tank Farms: Intrinsic safety protection for volatile liquid temperature tracking.

Integrated Diagnostic Functions

• EBD Alarm: Green LED pulses to indicate early burnout detection for thermocouples.
• NAMUR NE43 Compliance: Configurable out-of-range output characteristics for standardized fault reporting.
• Sensor Failure Drive: User-selectable upscale, downscale, or off modes upon signal loss.
• Status Monitoring: Real-time loop resistance monitoring to detect wiring degradation > 50 Ohm.

Shipping and Warranty Terms

• Warranty Policy: Includes a 12-month professional warranty.
• Express Logistics: Rapid fulfillment via FedEx, UPS, and DHL.
• Dispatch Window: Orders are typically shipped within 24-48 hours.
• Package Contents: One (1) New MTL4573 Converter with technical documentation.

Professional Engineering FAQ

Question: How is the MTL4573 configured for different sensor types?

Answer: Configuration requires a PC running PCS45 software connected via a PCL45USB serial interface to the module's front port.

Question: Does this module require a separate CJC sensor for thermocouples?

Answer: No, the HAZ-CJC plug on terminals 1-3 includes an integral sensor, though CJC can be disabled in software if required.

Question: Can I use the MTL4573 for simple resistance measurement without an RTD?

Answer: Yes, the module supports a resistance range of 0 to 400 Ohm with a minimum span of 10 Ohm.

Question: What is the benefit of 4-wire RTD wiring on this module?

Answer: The 4-wire setup provides the highest accuracy by completely compensating for all lead wire resistance errors.

Question: How does the Early Burnout Detection (EBD) work?

Answer: The module monitors loop resistance; if it increases by more than 50 Ohm, the EBD alarm triggers before full sensor failure.

Selection and Purchasing Guide

• Ensure your required temperature range meets the 3mV (THC) or 10-100 Ohm (RTD) minimum span requirements.
• Always verify the HAZ-CJC connector is used for thermocouple installations to ensure temperature accuracy.
• The unit consumes 50mA at 24V; verify your backplane power supply can accommodate the load.
• This module is designed specifically for high-density mounting on MTL backplanes.

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