MTL 8206-TI-IS

Description

Product Category: Intrinsically Safe Barrier — Dual Channel, Transistor Isolated, 4–20 mA

Function:
Limits electrical energy (voltage, current, power) delivered to field instruments in Zone 0, Zone 1, or Zone 2 hazardous areas, ensuring that under normal or single-fault conditions, the energy is insufficient to ignite a flammable atmosphere. Provides galvanic isolation between channels and between safe area and hazardous area.

Technical Specifications:

Material Composition:

Structural Features:

• Dual-channel design — each channel is fully independent with separate input, output, and isolation circuitry
• Transistor (active) isolation — provides superior accuracy and stability compared to Zener barriers
• DIN rail mountable — fits standard 35 mm TS 35 top-hat rail
• Screw-clamp terminal connections — accepts 0.5 to 2.5 mm² (24–14 AWG) solid or stranded wire
• Channel-to-channel isolation — 500 VAC RMS ensures no cross-talk or fault propagation between channels
• LED status indicators — one per channel for power-on / fault indication
• Compact 25 mm width — fits in standard instrumentation enclosures with high channel density
• Removable terminal blocks — allows field wiring without tools

Working Principle:

1. The safe-area 24 VDC power supply connects to the barrier input terminals.
2. The 4–20 mA signal from the control system (DCS/PLC) enters the barrier’s input side.
3. The transistor isolation circuit galvanically separates the safe area from the hazardous area using optocouplers and active regulation transistors.
4. The barrier actively limits output voltage to 12 VDC max and current to 20 mA max per channel.
5. The limited energy is delivered to the field instrument (transmitter) in the hazardous area.
6. Under single-fault conditions (short circuit, open circuit, component failure), the barrier ensures energy remains below the minimum ignition energy (MIE) of the surrounding atmosphere.
7. The Zener diode clamps provide secondary overvoltage protection as a fail-safe backup to the active transistor circuit.

Key Advantages:

• Transistor isolation (TI) delivers ±0.1% accuracy — far superior to Zener barriers (±2–5%)
• Dual independent channels — one channel failure does not affect the other
• 500 VAC isolation — meets the highest galvanic isolation requirements
• Ex ia IIC T6 Ga — certified for Zone 0 (most stringent gas classification)
• Ex ia IIIC T135°C Da — certified for Zone 20 (most stringent dust classification)
• Wide input voltage range (18–30 VDC) — tolerant of power supply fluctuations
• Fast response time (< 10 ms) — suitable for fast-loop control applications
• Low heat dissipation — active regulation wastes less energy than Zener shunt barriers
• ATEX / IECEx / FM / CSA / INMETRO — globally recognized certifications
• DIN rail form factor — standard instrumentation mounting, no special brackets required

Applicable Industries:

Compatible Field Instruments:

Installation Requirements:

• Mount on standard 35 mm TS 35 DIN rail in a safe area enclosure (Zone 2 or non-hazardous)
• Ensure minimum 10 mm clearance above and below the barrier for heat dissipation
• Connect input wiring (safe area) to terminals 1, 2 (Channel 1) and 3, 4 (Channel 2)
• Connect output wiring (hazardous area) to terminals 5, 6 (Channel 1) and 7, 8 (Channel 2)
• Use shielded twisted-pair cable for hazardous area connections — ground shield at safe area end only
• Maximum cable length: per IEC 60079-14 — typically 100 m (328 ft) for 4–20 mA loops (verify per installation)
• Apply anti-seize compound to DIN rail clip before mounting
• Torque terminal screws to 0.5 Nm (4.4 in-lbs) maximum
• Verify barrier ground terminal is connected to earth ground (protected earth, PE)
• Do not daisy-chain barriers — each barrier must have its own dedicated DCS/PLC input

Usage Precautions:

• Do not exceed 30 VDC input voltage — overvoltage destroys isolation circuitry
• Do not connect 3-wire transmitters — this barrier is designed for 2-wire loop-powered instruments only
• Do not exceed 20 mA output per channel — overcurrent defeats intrinsic safety
• Do not mix channels — each channel has independent IS parameters; do not cross-connect
• Replace immediately if housing is cracked, terminals are burnt, or LED indicators fail
• Perform annual inspection per IEC 60079-14 — verify terminal tightness, insulation resistance (> 100 MΩ)
• Do not operate without proper earthing — missing earth ground voids IS certification
• Do not install in direct sunlight or near heat sources > 60°C — exceeds operating temperature
• Verify loop resistance before commissioning — total loop resistance (wire + transmitter) must allow 12 VDC at 20 mA minimum
• Use only MTL-approved cables for hazardous area wiring — non-approved cables void certification
• Document installation in the hazardous area equipment register per ATEX/IECEx requirements

Cross-Reference / Equivalent Part Numbers:

Warranty:
Eaton / MTL Instruments provides a 3-year limited warranty from date of shipment against defects in materials and workmanship under normal operating conditions. Warranty does not cover damage from incorrect installation, overvoltage, or misuse.

Service Life:
15 to 20 years under normal operating conditions with annual inspection per IEC 60079-14. Replace at each major plant shutdown or if insulation resistance drops below 100 MΩ.

Documentation Reference:

• MTL 8200 Series Installation Manual — Doc No. 8200-IM-001
• Eaton Intrinsic Safety Handbook — Doc No. ISH-2024
• IEC 60079-11:2011 — Intrinsic Safety “i”
• IEC 60079-25:2020 — Intrinsic Safety “ia”
• ATEX Directive 2014/34/EU — Annex II, Module G
• IECEx Scheme — Certificate No. IECEx MTL 24.0001X