Honeywell MC-TAMR03 51309218-175 Field Termination Assembly

The Honeywell MC-TAMR03 51309218-175 is a Low-Level Analog Input Multiplexer Field Termination Assembly (LLMUX RTD FTA) designed for resistance temperature measurement applications within Honeywell control systems. The assembly provides field termination, signal routing, and sensor interface functions for low-level RTD inputs, supporting accurate temperature acquisition through multiplexer-based analog input architectures.

RTD Measurement Interface

MC-TAMR03 is designed specifically for RTD temperature sensing applications and supports:

• 10 Ohm RTDs

• 100 Ohm RTDs

• 120 Ohm RTDs

The assembly routes sensor signals between field wiring and the associated multiplexer processing hardware while maintaining measurement integrity for low-level resistance inputs.

A precision excitation current source is integrated into the measurement path, allowing accurate RTD resistance measurement and compensation of sensor circuit characteristics.

Multiplexer Architecture

Each FTA supports 16 RTD input channels. In Honeywell low-level analog multiplexer systems, multiple FTAs can be combined with a dedicated LLMUX processor to expand overall temperature monitoring capacity.

The assembly serves as the field wiring interface rather than performing signal processing itself. Analog conversion and multiplexing functions are handled by the associated processing hardware.

Measurement Performance

The LLMUX architecture provides one complete scan per second across all connected channels.

Key measurement characteristics include:

• 14-bit analog-to-digital resolution

• Typical accuracy: ±0.1 deg C

• Maximum accuracy error: ±0.5 deg C

• Automatic open-sensor diagnostics every 30 seconds

These capabilities support continuous monitoring of RTD circuits while providing fault detection for disconnected or failed sensors.

Isolation and Signal Integrity

The assembly provides galvanic isolation between field channels and the system interface, helping protect control system electronics from field-side electrical disturbances.

Isolation ratings are specified as:

• Up to 250 Vac peak

• Up to ±250 VDC

This isolation improves measurement reliability in electrically noisy industrial environments.

Installation and Construction

MC-TAMR03 uses screw-type compression terminals for field wiring termination. The assembly is supplied with conformal coating as standard, providing protection against moisture, dust, and corrosive atmospheres.

The module should be mounted in an upright orientation within an approved enclosure, consistent with the requirements of the associated multiplexer system architecture.

Technical Specifications

Diagnostic Features

The assembly continuously supports open-circuit sensor monitoring. Automatic diagnostics are executed every 30 seconds to identify disconnected RTDs and wiring faults, allowing maintenance personnel to quickly locate field issues.

Because the assembly handles low-level RTD signals, proper wiring practices and terminal integrity are important for maintaining specified measurement accuracy.

Frequently Asked Questions

Q: What sensor types can be connected to the MC-TAMR03?
A: The assembly is designed for RTD temperature sensing applications and supports 10 Ohm, 100 Ohm, and 120 Ohm RTD sensors.

Q: Does the MC-TAMR03 perform analog signal conversion?
A: The FTA provides field termination and signal routing functions for the LLMUX system. Measurement processing is performed by the associated multiplexer hardware.

Q: How are sensor failures detected?
A: The system performs automatic open-sensor diagnostics at 30-second intervals, allowing detection of disconnected sensors or wiring faults.