Honeywell 51305907‑175 (MC‑TAMR04) Low Level Analog Input Multiplexer

Product Description

51305907‑175, model MC‑TAMR04, is a rack‑mounted low‑level analog input multiplexer for Honeywell Experion PKS / UCN DCS systems. It adopts solid‑state relay switching technology and conformal coated PCB for moisture and chemical vapor resistance. This module collects weak low‑level signals such as RTD and millivolt thermocouple signals from field sensors, multiplexes multiple input channels and transmits conditioned signals to the matching analog input processor. It is installed in the I/O cabinet and designed for 24‑hour continuous operation in harsh process control environments.

Product Functions

• Multiplex multiple low‑level millivolt and RTD resistance signals from field temperature sensors
• Solid‑state relay channel switching with low noise to maintain signal integrity of weak analog inputs
• Transmit multiplexed sensor signals to the UCN analog input processor for A/D conversion
• Built‑in channel fault detection for open sensor wires and abnormal signal levels
• Work cooperatively with dedicated FTA terminal boards to complete field sensor wiring connection

• Provide accurate temperature measurement data for closed‑loop monitoring and control of industrial processes

  
  

Application Scenarios

• Petroleum refinery and chemical plant Experion PKS DCS temperature monitoring cabinets
• Thermal power station boiler, turbine and auxiliary equipment temperature acquisition systems
• Offshore platforms, LNG and natural gas processing factory process temperature measurement loops
• Pulp, paper and pharmaceutical continuous production temperature monitoring and control
• Spare‑part replacement and renovation of legacy Honeywell UCN distributed control systems

Common Problems

• Individual channel no valid temperature reading: Broken thermocouple/RTD sensor, loose FTA terminal, failed solid‑state switching relay on multiplexer board.
• Unstable, fluctuating measured values: Poor shielding of low‑level signal cables, strong electromagnetic interference or degraded internal signal conditioning circuit.
• DCS reports module fault alarm: Backplane connector oxidation, dust accumulation and overheating, incompatible firmware version with matched AI processor.
• All sensor signals lost simultaneously: Multiplexer internal power circuit damage or backplane communication bus failure.
• Intermittent signal dropout: High cabinet humidity causes circuit corrosion, poor card contact or vibration‑induced wiring loosening.