Description

Yokogawa AMM25C Analog Input Multiplexer Module

Configured for multi-channel mV and thermocouple signal acquisition in CENTUM CS and CENTUM VP systems, the Yokogawa AMM25C (AMM25C Analog Input Multiplexer Module) provides direct physical/electrical execution. The module multiplexes low-level DC voltage and thermocouple inputs through isolated acquisition paths with reference junction compensation (RJC) support, enabling structured signal conditioning for distributed I/O architectures. Channel isolation and burnout detection logic are implemented at hardware level.

Suffix Breakdown & Model Matrix

AMM25C: Fixed model designation for mV input multiplexer module
No additional suffix variants or ordering extensions specified in provided data.

Hardware Specifications

Parameter	Specification
ModelBrand	Yokogawa AMM25C
Origin	Japan (Yokogawa Electric Corporation)
Weight	2 kg
Dimensions	2.5 cm x 22.9 cm x 7.6 cm
OperatingTemp	Not specified
PowerConsumption	Not specified
Input Channels	15 points
Input Types	DC voltage, mV DC, thermocouple
Input Range	-10 VDC to 10 VDC, -100 mVDC to 100 mVDC
Accuracy	±40 uV (mV input), ±80 uV/10 degC ambient change
Isolation	Input channel isolation
Burnout Detection	UP / DOWN / OFF selectable
System Compatibility	CENTUM CS, CENTUM VP

Yokogawa Cold Junction Compensation & Channel Isolation Architecture

The AMM25C implements cold junction compensation (CJC) via dedicated RJC input interface to stabilize thermocouple reference junction drift under varying terminal block temperature conditions. Channel-to-channel electrical isolation is used to reduce cross-interference between multiplexed low-level analog signals. In CENTUM VP integration, the module supports deterministic scan acquisition aligned with DCS backplane scheduling, maintaining stable sampling integrity across mixed mV and thermocouple input configurations.

Frequently Asked Questions

Q: Can the AMM25C handle simultaneous thermocouple and mV DC inputs?
A: Yes. Input multiplexing hardware supports mixed signal types across 15 input channels with shared acquisition timing.

Q: Does the module perform cold junction compensation internally?
A: It supports RJC-based reference junction compensation through its dedicated input port.

Q: What happens on thermocouple burnout detection?
A: The module allows selectable burnout behavior: UP, DOWN, or OFF at hardware configuration level.

Field Installation Guidelines

Mount the AMM25C module into standard I/O nest assembly using S1 terminal block configuration. Secure installation using M4 screws with KS1 cable connection system. Maintain separation between thermocouple input wiring and high-voltage conductors to reduce thermoelectric noise coupling. Ensure shield termination is grounded at single-point earth reference to avoid ground loop formation in low-mV signal paths. Verify correct RJC sensor placement before system energization to maintain valid cold junction reference.

Specifications

• Brand: Yokogawa

Advantages

• High reliability in industrial environments
• Supports continuous operation
• Compatible with major PLC/DCS systems