Yokogawa AMM32T RTD Input Multiplexer Module

Configured for high-density temperature acquisition in Centum CS and Centum VP control architectures, the Yokogawa AMM32T (AMM32T) RTD Input Multiplexer Module provides direct physical/electrical execution of 32-channel isolation, sensor resistance-to-digital conversion, and backplane-to-field signal multiplexing.

Hardware Specifications

Yokogawa DCS Process Control Characteristics

• 4-20 mA HART loop protocol: The AMM32T module functions as the interface between field-mounted RTD sensors and the DCS. While RTDs are inherently resistive, the module architecture ensures that the converted digital signals are synchronized with the DCS loop scan cycle, facilitating accurate temperature data for HART-managed process control.
• FOUNDATION Fieldbus / Profibus PA connectivity: The multiplexer integrates into the Centum I/O bus, allowing the system to aggregate 32 channels of temperature data into a single controller interface. This data density is mandatory for maintaining the deterministic timing required for large-scale temperature monitoring networks.
• Channel-to-channel isolation: Each of the 32 input channels is galvanically isolated. This is mandatory to prevent ground-referenced noise from high-voltage equipment in the process area from interfering with low-level RTD resistance measurements across the multiplexer bank.
• Cold junction compensation (CJC): The module assembly utilizes precision reference resistors to compensate for lead-wire resistance and ambient temperature drift at the connection terminals. This is mandatory to maintain the high-precision temperature measurements (Pt100/Pt1000/JPT100) required for critical process optimization.

Frequently Asked Questions

Q: Does the AMM32T support hot-swapping within the Centum I/O rack?

A: No. Power must be isolated from the module and the rack must be soft-inhibited in the Centum configuration before physical removal. Hot-swapping can trigger an electrical spike on the backplane, potentially damaging the multiplexer's sensitive switching components and corrupting data across the entire 32-channel block.

Q: How can the AMM32T be expanded using the AMT16R module?

A: The AMM32T is engineered to interface with the AMT16R to augment the total point density within the Centum cabinet. Integration must be performed according to the specific rack-spacing and power-loading requirements defined in the Yokogawa I/O expansion manual to prevent backplane overcurrent conditions.

Field Installation Guidelines

• Mounting: Seat the AMM32T securely into the rack slot. Ensure that the backplane connector is fully engaged, as high-density I/O modules require stable seating to maintain the integrity of the multiplexing bus signal.
• Grounding: Terminate the module’s chassis ground to the cabinet’s dedicated instrument earth bus using a low-impedance connection. This is mandatory to ensure the efficacy of the channel-to-channel isolation and to protect the module from transient surges in high-noise environments.
• Wiring: Terminate RTD leads using shielded, twisted-pair cabling. Maintain at least 150 mm separation from high-voltage AC lines to prevent inductive coupling, which is mandatory to protect the high-precision resistance measurements from induced electrical noise.