Eaton MTL5549

Core Technical & Performance Parameters

• Hazardous Area Certification: Ex ia IIC T6 Ga, Zone 0 / Zone 1 gas hazardous locations
• Channel Configuration: Dual fully independent HART 4-20mA loop channels
• Supported Field Device: 2-wire loop-powered HART transmitters (pressure, level, flow, temperature)
• HART Protocol Support: HART 5, HART 6, HART 7 full compatibility
• Loop Power Output: Regulated intrinsically safe 24V DC per channel
• Galvanic Isolation Voltage: 2500 VAC between hazardous and safe circuit domains
• Maximum Safe Circuit Parameters: Ui=28V, Ii=93mA, Pi=1.3W per channel
• Analog Signal Transfer Accuracy: ±0.1% full scale 4-20mA measurement error
• Operating Ambient Temperature: -20°C ~ +60°C
• Safety Integrity Level: SIL 2 certified for analog safety measurement loops

Functional Features

1. Dual-channel high-density design doubles cabinet signal packing density versus single-channel barriers
2. Full bandwidth preservation for HART digital communication signals, transparent remote calibration & diagnostics
3. Independent intrinsic safety energy limiting circuits for each channel, cross-channel fault isolation
4. High galvanic isolation eliminates industrial ground loop interference and common-mode noise distortion
5. Ultra-low analog signal transfer error for high-precision process variable monitoring
6. Per-channel reverse polarity wiring protection for field instrument installation tolerance
7. Wide temperature operating range compatible with unheated industrial control cabinets

Working Principle

Material Composition

• Housing: Black anti-static V0 flame retardant ABS plastic
• Isolation Hardware: Two independent low-distortion high-frequency isolation transformers optimized for HART signal bandwidth
• Safety Limiting Circuits: Precision Zener diodes, low-temperature drift wire-wound resistors, ceramic gas discharge surge tubes
• Terminals: Nickel-plated copper screw terminals with PA66 flame retardant plastic housing
• Mounting Components: Zinc-plated spring steel DIN rail mounting clips

Structural Characteristics

1. Double-width DIN rail module integrating two fully isolated HART signal channels
2. Segmented terminal blocks: left hazardous field side dual channel terminals, right safe cabinet DCS dual channel terminals
3. Dual front-panel LED power indicators to visually confirm active loop power for each transmitter channel
4. Removable transparent plastic terminal safety cover for maintenance wiring protection

Installation Requirements

1. Mount only inside non-hazardous safe-area control cabinets; field cables routed into Zone 0/1 hazardous enclosures
2. Maintain minimum 5mm vertical air gap between adjacent MTL series barrier modules for heat dissipation
3. Hazardous field instrument cables must use intrinsically safe shielded twisted pair cable, single-ended shield grounding at cabinet PE bar
4. Maximum field cable total loop resistance limited to 500Ω per channel to maintain stable HART communication
5. Torque all terminal screw connections to standardized 0.8 N·m torque to prevent contact resistance fluctuation
6. Separate field instrument wiring from high-current AC power cables with minimum 25cm physical separation distance
7. Cabinet ventilation mandatory for continuous operation above +55°C ambient temperature

Application Scenarios

• Oil & gas Zone 0 tank farm dual-channel HART level/pressure transmitter signal isolation
• Refinery distillation unit hazardous zone paired temperature & flow HART instrument barriers
• Chemical reactor Zone 1 dual analytical transmitter intrinsic safety signal isolation
• Offshore FPSO process monitoring multi-point HART transmitter dual-channel barrier systems
• Fertilizer plant explosion-proof production line paired pressure & pH HART measurement loops

Operation & Maintenance Precautions

1. Dedicated exclusively for 2-wire loop-powered HART transmitters; select MTL5544 model for 4-wire separately powered instruments
2. HART handheld calibrator must connect to safe-side DCS terminals only, never hazardous field terminals
3. Annual analog signal transfer calibration required for SIL 2 safety instrumented measurement loops
4. If HART communication signal loss occurs, inspect field cable total loop resistance for excessive resistance value
5. Do not apply DC voltage exceeding 28V to hazardous field side terminal blocks
6. Replace module immediately if measured signal transfer error exceeds ±0.3% full scale during routine testing
7. Keep cabinet internal relative humidity below 80% non-condensing to prevent PCB surface leakage current