Eaton MTL 4641 – Intrinsically Safe Repeater Power Supply for 2‑wire transmitters with HART transparency

The MTL 4641 is part of the MTL 4600 series of galvanically isolated interfaces, built for hazardous area process loops where you need clean, stable 24V powering of a 2‑wire transmitter in Zone 0/1 and a faithful 4–20mA signal on the safe side. From my experience, it’s the “fit-and-forget” choice when you want reliable loop isolation, HART pass-through, and a slim footprint on a carrier backplane. You might notice that it drops straight into mixed I/O panels where temperature, pressure, and level transmitters need certified intrinsic safety without babysitting each channel.

Company’s Order Placement Process and Guarantees

• Warranty: 365 days
• Delivery: 1 week for items in stock; no more than one month at the latest
• Payment: 50% advance payment; full payment before delivery
• Express options: FedEx, UPS, DHL

Key Features

• Repeater power supply for 2‑wire transmitters – Powers an Ex ia field device and reproduces a matching 4–20mA on the safe side.
• Galvanic isolation – Breaks ground loops and improves measurement stability in noisy plants.
• HART transparent – Maintains bidirectional HART communication in most setups without extra wiring.
• Compact, carrier/backplane mounting – Slim profile to maximize channel density on DIN-rail carriers.
• Designed for hazardous areas – Typically applied between Zone 0/1 transmitters and safe-area control systems.
• Stable loop performance – Low drift and robust isolation for steady, accurate analog readings.

One thing I appreciate is how straightforward it is to commission: wire the hazardous-side 2‑wire transmitter, land the safe-side 4–20mA into your AI card, and HART tools typically connect as usual. In many cases, the loop comes up clean with minimal tuning.

Technical Specifications

Note: Specifications reflect the MTL 4600 family characteristics and the typical role of model 4641 as a repeater power supply. For project-critical parameters, we typically verify against the latest manufacturer datasheet before shipment.

Related or Supporting Products

• MTL 5541 – DIN‑rail equivalent repeater power supply from the MTL 5500 series; similar function if you prefer discrete DIN modules instead of a backplane format.
• MTL 4541 – Backplane family alternative in the 4500 series; often used in legacy panels where the carrier is already installed.
• MTL HART maintenance tools – Portable HART modems and handhelds for configuration through the 4641 loop without breaking isolation.
• MTL 4600 series carriers & power rails – Backplanes that supply DC power and commoning for multiple modules, keeping wiring neat and scalable.

A customer in a gas compression skids project swapped to MTL 4641 on an existing 4600 carrier and immediately freed half a rail thanks to the slim profile—no changes needed on the DCS side, HART diagnostics worked as expected.

Installation & Maintenance

• Panel environment – Mount on a compatible MTL 4600 series carrier on a grounded DIN rail inside an IP-rated cabinet. Provide ventilation; avoid hotspots near VFDs.
• Wiring practice – Keep hazardous-area field wiring segregated from safe-area runs. Use twisted pair/shielded cable for analog loops; terminate shields at one end to minimize ground noise.
• Earthing – Bond the carrier/rail as recommended by MTL to ensure the specified isolation and EMC performance.
• HART access – Most cases allow clipping the HART modem across the AI card or across the safe-side loop terminals; no special HART resistor is usually needed with repeater power supplies.
• Routine checks – Verify loop current at 0/50/100% points annually; check terminal torque and inspect for dust build-up. Firmware isn’t typically required on passive analog isolators, so maintenance is light.
• Safety – Confirm the entity parameters and gas group/temperature class of the field device match the module’s Ex ia approvals before commissioning.

Quality & Certifications

• CE compliant; designed for EMC and low-voltage directives
• ATEX / IECEx intrinsic safety for Ex ia applications (typical for MTL 4600 family)
• UL/cUL for ordinary locations; many installations accept it in North American panels
• RoHS compliant manufacturing
• Manufacturer’s warranty: 12 months (365 days)

If you’re standardizing a mixed fleet of transmitters and want consistent IS loop behavior across skids, MTL 4641 typically makes life easier—clean isolation, compact format, and HART transparency without extra accessories.