Description

The MTL4541AS is a single-channel, intrinsically safe (IS) galvanic isolator designed to interface with 4 to 20 mA transmitters located in hazardous areas. This “AS” variant is specifically engineered for “Active Sink” or specific controller-powered applications, facilitating a transparent connection between hazardous area field devices and safe area control systems (DCS/PLC).

Commercial Availability & Lifecycle Status

• Condition: New Original (Factory Sealed)

• Availability: High Stock Volume

• Standard Lead Time: Ships within 24 hours

• Warranty: 12-Month Standard Industrial Warranty

• Pricing Note: As a high-volume interface component, pricing is competitive for bulk orders. Contact our sales department for project-based discounts.

Technical Specifications

Technical Implementation & Field Considerations

The “AS” Designation: Current Sink vs. Current Source

The MTL4541AS differs from the standard MTL4541. In the AS version, the safe-area output acts as a current sink. This means the safe-area equipment (the PLC analog input card) must provide the loop power. This is critical for compatibility with specific DCS I/O cards that are hard-wired to source power from their input terminals.

Warning: Using an MTL4541AS with an I/O card that is also configured as a “Sink” will result in a non-functional loop, as there will be no voltage source to drive the current.

Backplane Integration

The MTL4541AS is part of the MTL4500 series, designed for high-density mounting on MTL CPS series backplanes. It utilizes a plug-in design that simplifies maintenance, allowing for “Hot Swapping” without disconnecting individual field wires. This reduces downtime during module replacement in critical 24/7 process loops.

HART Compatibility

The module supports bi-directional HART (Highway Addressable Remote Transducer) digital communication. It allows HART signals to pass through the galvanic isolation barrier, enabling remote calibration, diagnostics, and monitoring of field instruments via a HART hand-held communicator or an Asset Management System (AMS) connected at the safe-area terminals.

Safety Integrity Level (SIL)

The MTL4541AS is rated for use in safety-related systems up to SIL 2 (per IEC 61508) in terms of functional safety. When used in a redundant configuration or as part of a verified safety instrumented function (SIF), it provides the necessary reliability for emergency shutdown (ESD) systems.

Frequently Asked Questions

What is the difference between the MTL4541 and the MTL4541AS?

The standard MTL4541 sources current to the safe-area load (it provides the power). The MTL4541AS sinks current (the safe-area equipment must provide the power). Verify your PLC/DCS input card manual before selection.

Can I use this with a 2-wire transmitter?

Yes, the MTL4541AS is primarily designed to provide the 16.5 V DC supply required to power 2-wire transmitters located in the hazardous area. It can also be used with powered 4-wire transmitters if the input is configured correctly.

Do I need to ground the IS barrier?

Unlike Zener barriers, the MTL4541AS is a galvanically isolated barrier. It does not require a high-integrity “IS Ground” (Earth). This makes it more resilient to ground loops and signal noise in large-scale plant environments.

What is the maximum cable length supported on the field side?

The maximum length is determined by the total loop resistance (cable resistance + transmitter minimum operating voltage). The module provides > 16.5 V. If your transmitter requires 12 V, you have 4.5 V of “headroom” for cable drop, which at 20 mA ($V=IR$) allows for up to 225 Ohms of cable resistance.

Do you need the specific backplane part numbers for a new installation, or are you replacing an existing unit in a legacy MTL4000 series system?