Why the MTL5575 Solves Temperature Conversion Challenges

When temperature signal accuracy is critical in hazardous environments, the MTL5575 delivers reliable THC or RTD input and alarm functionality. This single-channel converter from the Eaton Crouse-Hinds series MTL5500 family handles thermocouple, millivolt, and RTD signals with a configurable response time of 500ms default. Its 4-20mA nominal output into 600Ω max ensures compatibility with standard control systems, while the 250V rms galvanic isolation between safe-area circuits and power supply protects against ground loops and noise.

Key Features & Technical Specs

• Input signal range of -75mV to +75mV supports multiple THC types and RTDs 2/3/4-wire.
• Power supply of 20-35 Vdc with 50mA current consumption and 1.2W dissipation.
• Cold junction compensation error ≤1.0°C with automatic or selectable mode.
• Common mode rejection of 120 dB for 240V at 50 or 60 Hz.
• Series mode rejection of 40 dB for 50 or 60 Hz.
• LED indication: green for power, yellow for status.
• Safety drive on sensor failure: upscale, downscale, or off.
• Early burnout detection for thermocouples when selected.

One distinctive spec is the 200µA RTD excitation current, which minimizes self-heating errors in RTD sensors, improving long-term measurement stability.

Real-World Applications

In oil and gas refineries, the MTL5575 monitors temperature in Zone 0 hazardous areas, converting signals from thermocouples or RTDs to a 4-20mA loop. For chemical processing plants, its configurable alarm thresholds provide early warning of temperature excursions, preventing equipment damage. The unit’s 5-95% relative humidity tolerance makes it suitable for outdoor installations in humid climates.

Installation & Setup

Mount the MTL5575 on a T-section 35mm DIN rail using the provided mounting method. Connect conductors up to 2.5mm² stranded or single-core using crimp ferrules. Configure the unit via a personal computer running MTL PCS45 software with a PCL45USB serial interface. Set the safety drive on sensor failure to upscale, downscale, or off based on your process requirements.

Maintenance & Reliability

Routine inspection of the MTL5575 involves verifying LED indicators: green for power and yellow for status. The unit’s 1.2W power dissipation ensures minimal heat buildup, extending component life. With an ambient operating temperature range of -20°C to 60°C and storage range of -40°C to 80°C, this converter withstands harsh industrial conditions. The 5-95% relative humidity rating further enhances reliability in moist environments.

Compatibility & Integration

The MTL5575 integrates with standard 4-20mA control systems and PLCs. Its 600Ω maximum load resistance allows connection to long cable runs without signal degradation. The unit complies with EN61326 EMC standards, ensuring electromagnetic compatibility in industrial settings. For configuration, use the MTL PCS45 software and PCL45USB interface, which are available separately.

FAQs about the MTL5575

Q: What input signal types does the MTL5575 accept?

A: It accepts THC types, millivolt signals, and RTDs 2/3/4-wire within a -75mV to +75mV range.

Q: What is the default response time?

A: The response time is configurable with a default of 500ms.

Q: How is the MTL5575 powered?

A: It requires a 20-35 Vdc power supply and consumes 50mA.

Q: What happens if the sensor fails?

A: The safety drive can be set to upscale, downscale, or off.

Q: What is the cold junction compensation error?

A: It is ≤1.0°C with automatic or selectable compensation.

Product Support & Availability

The MTL5575 is in stock and ready to ship from PetroPartsOnline. Contact our team for pricing and lead times. We support industrial automation and oil/gas parts supply with fast delivery.