MTL F860-CA

Description

Technical Specifications

• Bus Protocol Standard: FOUNDATION Fieldbus H1 IEC 61158-2, 31.25 kbps Manchester encoded signal
• Channel Configuration: Single full fieldbus trunk channel (multi-drop support for up to 16 fieldbus transmitters per hazardous segment)
• Safe Side Supply Rating: Nominal 24 VDC; operating input range 18 VDC – 32 VDC
• Intrinsic Safety Hazardous Side Parameters (Ex ia IIC):
  • Voc = 24 VDC
  • Isc = 110 mA
  • Max permissible Ci = 0.12 μF
  • Max permissible Li = 12 mH
• Galvanic Isolation Strength: 2500 VAC reinforced isolation between safe zone and hazardous zone circuits
• Surge Protection Rating: Built-in 8/20 μs surge arrester, withstand 10 kA surge current per IEC 61643-21
• Signal Delay: ≤ 12 μs bus signal propagation latency
• Power Consumption: Max 1.2 W under full bus load
• Environmental Ratings:
  • Operating Temperature: -20 °C ~ +65 °C
  • Storage Temperature: -40 °C ~ +90 °C
  • Protection Class: IP20 (safe cabinet mounting only)
• Mechanical Dimensions: 122 mm (H) × 68 mm (D) × 22.5 mm (W)
• Net Weight: 0.22 kg
• Certifications: ATEX II 1G Ex ia IIC, IECEx ia IIC, UL IS, EN 60079-11, IEC 61158-2, CE

Function Features

1. Integrated three-stage protection: galvanic isolation, intrinsic safety energy limiting, lightning surge suppression in single compact unit
2. Full multi-drop FOUNDATION Fieldbus H1 compatibility, supports standard fieldbus segment termination resistance circuitry
3. Bidirectional transparent bus signal transmission without signal distortion or bandwidth reduction
4. Built-in reverse supply polarity protection for safe-side power input
5. Front panel dual LED indicators: power status LED, bus communication activity LED
6. DIN rail modular design, hot-pluggable without full fieldbus segment shutdown
7. Separate labeled terminal blocks for safe-side controller bus wiring and hazardous-side field trunk wiring

Material Composition

• Housing: UL94-V0 flame-retardant polycarbonate industrial plastic
• PCB: High-temperature FR4 fiberglass circuit board with tin-nickel plated traces
• Isolation Core: Reinforced winding isolation transformer with 2500 VAC dielectric withstand
• Safety Components: Precision wirewound current limit resistors, Zener voltage clamping diodes, gas discharge surge arresters, TVS transient suppressors
• Terminals: Copper alloy screw terminals with anti-corrosion nickel plating

Structural Characteristics

• 22.5 mm slim DIN rail housing for high-density cabinet layout
• Front terminal zone physically split with molded plastic divider to separate safe-side and hazardous-side wiring terminals
• Rear spring-loaded DIN rail locking clip for rapid installation and removal
• Fully potted internal circuit assembly to block dust, moisture and mechanical component displacement
• Front vertical LED indicator array for real-time visual bus health diagnosis
• Internal EMI shielding partitions to eliminate fieldbus signal interference from industrial power wiring

Working Principle

1. Safe-area FOUNDATION Fieldbus H1 signal and 24 VDC bus power enter the safe-side primary winding of the isolation transformer; conductive electrical connection between safe and hazardous circuits is fully eliminated
2. Precision Zener and resistor energy limiting circuits continuously clamp voltage and current supplied to hazardous fieldbus trunk to non-ignition levels compliant with Ex ia IIC standards
3. Integrated gas discharge surge arresters divert lightning-induced high-voltage transients to cabinet protective earth before surge energy reaches hazardous field wiring
4. Transformer secondary winding delivers isolated, safety-limited power and digital fieldbus signals to multi-drop field instruments in hazardous zones
5. Bidirectional signal transmission supports host controller read/write access to all fieldbus device parameters without signal attenuation or protocol modification

Advantage Highlights

1. All-in-one integration of isolation, intrinsic safety and surge protection eliminates three separate discrete components, reducing cabinet space and wiring workload
2. 2500 VAC reinforced isolation fully mitigates ground loop noise and cross-circuit interference on fieldbus networks
3. Ex ia IIC certification permits direct connection to Zone 0 hydrogen-class hazardous fieldbus devices
4. Native FOUNDATION Fieldbus H1 compliance requires no external signal conditioning adapters
5. Built-in visual LED diagnostics enable on-site rapid fieldbus fault location without portable test equipment
6. Wide temperature operating range compatible with unconditioned industrial control cabinets for refinery and offshore installations

Applicable Industries

Oil & gas upstream offshore platforms, refinery hazardous area FOUNDATION Fieldbus control networks, petrochemical plant reactor monitoring, LNG storage terminal fieldbus instrumentation, pharmaceutical solvent processing plants, chemical fertilizer explosive gas zone measurement systems

Installation Requirements

1. Install exclusively inside non-hazardous IP20 rated safe-area control cabinets; mounting within Ex Zone 0 / Zone 1 is prohibited.
2. Mount on standard 35 mm DIN rail with minimum 5 mm vertical clearance between adjacent modules for heat dissipation.
3. Safe-side and hazardous-side wiring must run through separate cable conduits with minimum 10 cm physical separation inside cabinet trunking.
4. Hazardous fieldbus cable must be certified intrinsically safe fieldbus cable with dedicated screen single-point earth grounding at cabinet earth bar.
5. Install external bulkhead surge protection at all cabinet cable entry points for long-distance fieldbus trunk runs over 30 meters.
6. Cabinet ambient humidity maintained at 5% – 95% non-condensing.
7. Fieldbus segment termination resistor must be installed at the furthest hazardous field device per FOUNDATION Fieldbus wiring specifications.

Usage Precautions

1. Do not apply safe-side supply voltage exceeding 32 VDC; overvoltage permanently damages internal safety limiting components and voids all intrinsic safety certifications.
2. Total hazardous segment cable capacitance and inductance must not exceed Ci=0.12 μF, Li=12 mH to eliminate ignition risk.
3. Never cross-connect safe-side terminals with hazardous-side terminals; this bypasses all intrinsic safety protection circuits.
4. Disassembling the unit or removing internal potting compound invalidates ATEX and IECEx safety approvals and product warranty.
5. Terminal screw tightening torque limited to 0.6 N·m; over-tightening fractures plastic terminal bases and PCB traces.
6. Annual bus communication and insulation resistance testing mandatory to maintain site process safety compliance.
7. Do not connect inductive or capacitive loads directly to hazardous-side terminals without matching IS-certified fieldbus transmitters.