Eaton MTL4842

Core Technical & Performance Parameters

• Hazardous Area Certification: Ex nA IIC T4 Gc, Zone 2 Category 3G certified
• Supported Field Loops: Max 16 channel HART 2-wire 4-20mA transmitter circuits
• HART Protocol Compatibility: HART 5, HART 6, HART 7
• Multiplex Communication Bus: RS485 multi-drop serial bus
• Maximum Bus Cable Length: 1200 meters STP cable
• Operating Temperature Range: -40°C ~ +70°C
• Enclosure Protection: IP20, install inside Zone 2 certified electrical enclosures
• Loop Power Output: Regulated 24V DC intrinsically safe power per field channel
• Channel Diagnostic: Per-channel short-circuit and open-circuit wiring fault detection
• DIN Rail Mount Standard: 35mm top-hat rail

Functional Features

1. 16-channel HART signal aggregation drastically cuts field multi-core cable installation cost
2. Per-channel independent loop power supply and wiring fault diagnostic monitoring
3. Ex nA non-sparking certification for Zone 2 low-risk explosive environments
4. Bidirectional transparent HART digital communication for remote instrument calibration and diagnostics
5. Daisy-chain RS485 bus architecture supporting multiple MTL4842 slave modules on single bus
6. Low power consumption design minimizing heat accumulation inside sealed Zone 2 enclosures
7. LED channel status indicators for quick on-site wiring fault troubleshooting

Working Principle

Material Composition

• Main Housing: Black flame retardant V0 ABS plastic anti-static formulation
• Multiplexing PCB: High-temperature FR4 tin-free solder circuit board
• Loop Power Circuits: Low-noise linear regulated power ICs, surge protection gas discharge tubes
• Terminal Blocks: Nickel-plated copper screw terminals, PA66 flame retardant plastic
• Mounting Clips: Zinc-plated spring steel DIN rail fasteners

Structural Characteristics

1. Wide multi-channel DIN rail module form factor
2. Front panel segmented terminal blocks grouped in 4-channel segments for simplified wiring organization
3. Individual bi-color LED status indicator for every single field channel
4. Separate RS485 bus terminal strip for daisy-chain master/slave module connection
5. Removable full-width terminal cover for safe wiring maintenance access

Installation Requirements

1. Install exclusively inside IECEx/ATEX certified Zone 2 electrical enclosures with minimum IP54 rating
2. Vertical DIN rail mounting required; maintain minimum 10mm vertical clearance above/below module for airflow
3. RS485 bus cable must use shielded twisted pair, bus shield grounded single-ended at safe-area MTL4850 cabinet
4. Maximum 8 units of MTL4842 slave modules allowed on one single MTL4850 master bus segment
5. All field transmitter wiring must use shielded twisted pair intrinsically safe instrument cables
6. Terminate unused RS485 bus endpoints with factory-supplied 120Ω matching resistors
7. Do not mount module adjacent to heat-generating power transformers or contactors inside enclosure

Application Scenarios

• Refinery Zone 2 process area mass HART instrument signal concentration
• Natural gas compressor station Zone 2 multi-transmitter multiplexing
• Petrochemical intermediate storage tank farm Zone 2 monitoring systems
• Water treatment chemical dosing plant Class I Div 2 hazardous instrumentation
• Coal-fired power plant flue gas desulfurization Zone 2 measurement loops

Operation & Maintenance Precautions

1. MTL4842 only compatible with MTL4850 master multiplexer module; cannot operate standalone
2. Avoid exceeding maximum 16 channel field load capacity per unit
3. Verify RS485 bus termination resistor installation at both bus endpoints during commissioning
4. Ambient enclosure temperature must not exceed +70°C continuous operating limit
5. Do not connect Zone 0 certified intrinsically safe instruments without additional Ex ia barrier upstream
6. Annual full channel wiring fault diagnostic test required for process monitoring reliability
7. Keep enclosure internal air circulation unobstructed to prevent overheating-induced signal drift