Eaton MTL4544S Dual-Channel Repeater Power Supply for HART and 4-20 mA Transmitter Loops

Eaton MTL4544S is a two-channel galvanic isolator from the backplane-mounted MTL4500 range. It supplies power to conventional 2-wire or 3-wire transmitters in a hazardous area and transfers each 4-20 mA signal to the safe-area control system. Unlike the standard output version, MTL4544S operates as a current sink at the safe-area connection. This distinction must be confirmed before a replacement is ordered.

Where the MTL4544S fits in an intrinsically safe analog loop

The hazardous-area side of MTL4544S provides fully floating DC supplies for two field transmitters. The module then repeats the two measured currents in separate safe-area circuits. Galvanic isolation separates the field wiring from the control-system side and helps the complete loop meet the selected intrinsic-safety concept when the barrier, field device, cable, earthing, and installation conditions are correctly engineered.

For compatible smart transmitters, MTL4544S supports bidirectional HART communication superimposed on the analog current at terminals 1 and 2 and terminals 4 and 5. A separately powered 4-wire current source can also be connected, but Eaton notes that HART communication is not supported in that arrangement.

Output and operating data for engineering review

Number of channels: two.

Safe-area signal range: 4 to 20 mA; under-range and over-range: 0 to 24 mA.

MTL4544S current-sink load: 600 ohms maximum; maximum external voltage source: 24 V DC.

Hazardous-area input range: 0 to 24 mA, including over-range.

Transmitter voltage reference: 16.5 V at 20 mA.

Transfer accuracy at 20 degrees Celsius: better than 15 microamps.

Temperature drift: less than 0.8 microamps per degree Celsius.

Response time: settles within 10 percent of final value within 50 microseconds.

Module supply: 20 to 35 V DC; maximum current consumption: 96 mA at 24 V DC with 20 mA signals.

Power dissipation for the sink-output version: 1.9 W at 24 V DC.

Safety data and installation limits

For each channel, Eaton lists Uo 28 V, Io 93 mA, Po 651 mW, and Um 253 V rms or DC. The transmitter location is referenced as Zone 0, IIC, T4-T6 when the connected transmitter is suitably certified; North American documentation also references Division 1, Group A. These figures do not replace a loop calculation. Cable capacitance and inductance, gas group, temperature class, certificates, and the field-device entity parameters must all be checked for the actual installation.

Replacement checks before ordering

• Record the complete MTL4544S catalog number and photograph the front and side labels.

• Confirm two independent 4-20 mA channels and the required current-sink safe-area input arrangement.

• Identify whether HART communication is required on either channel.

• Compare terminal assignments, backplane type, supply voltage, and control-card input specification.

• State the required quantity, delivery deadline, destination country, and certificate requirements.

Related models often reviewed with MTL4544S include MTL4544, MTL4544A, MTL4544AS, MTL4544D, MTL5544, MTL5544S, MTL4541S, MTL4541AS, MTL4575, MTL4517, MTL4524, MTL5517, MTL5521, MTL5531, and MTL5582B.

Sunup-MTL can assist with MTL4544S model confirmation, availability, quotation, export packing, and international delivery for maintenance and project requirements.