Description

Yokogawa AMM21 Combination Digital I/O Module

Configured for discrete signal acquisition and output switching in CENTUM CS and CENTUM CS 3000 Remote I/O (RIO) subsystems, the Yokogawa AMM21 (AMM21 Combination Digital I/O Module) provides direct physical/electrical execution of 16-channel input monitoring and 16-channel transistor output control within a single slide-in rack module architecture.

Suffix Breakdown & Model Matrix

AMM21 is referenced as a base module identifier within Yokogawa RIO digital I/O families. Common style variants (e.g., Style S2, Style S3) indicate mechanical and backplane compatibility revisions. No functional channel reconfiguration is defined at base model level; I/O density remains fixed at 16 DI + 16 DO.

Hardware Specifications

Parameter	Specification
ModelBrand	Yokogawa AMM21
Origin	Japan
Weight	0.4 kg
Dimensions	12.7 x 2.5 x 20.3 cm
OperatingTemp	Not explicitly specified (typical RIO cabinet ambient industrial rating applies)
PowerConsumption	Approx. 3 W
Input Channels	16 x Digital Input (dry contact / open collector)
Output Channels	16 x Digital Output (transistor sink type)
Output Load	24 VDC / 30 VDC nominal
Output Current	50 mA to 100 mA per channel
Isolation	Optical isolation, up to 1500 VAC withstand (1 min)

Channel-to-Channel Isolation and CENTUM RIO Signal Structuring

Within the Yokogawa CENTUM CS/CS 3000 RIO architecture, the AMM21 implements optocoupler-based galvanic separation between field inputs and system backplane logic. The digital input stage conditions dry contact transitions while suppressing induced noise on long field wiring. Output transistor stages operate as current-sink drivers intended for relay interposing, lamp indicators, and low-energy solenoid interfaces. Signal segmentation is handled at module level, limiting cross-channel electrical coupling under standard cabinet grounding practice.

Frequently Asked Questions

Q: Can AMM21 outputs drive direct actuator loads?
A: No. Output channels are transistor sinks rated for low-current loads only. External interposing relays are required for inductive or high-power loads.

Q: Does the module support hot-swapping in RIO racks?
A: Hot-swap capability depends on the specific CENTUM RIO base unit configuration. Electrical design assumes system power isolation prior to module replacement.

Q: Are input channels internally isolated per point?
A: Inputs are grouped with optocoupler isolation from system logic, but per-channel isolation details are not independently segmented at field level.

Field Installation Guidelines

Ensure RIO rack power is fully isolated before insertion or removal of the AMM21 module. Maintain proper shielding and single-point grounding for field cable shields at the cabinet entry. Avoid routing input and output wiring in the same high-current conduit to minimize induced coupling. Verify correct seating of the multi-pin backplane connector before energizing the system. For transistor outputs, include flyback suppression across inductive loads when applicable.

Specifications

• Brand: Yokogawa

Advantages

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