AMN21 | Yokogawa Nest for Relay I/O Modules | New

Product Overview

The Yokogawa AMN21 is an I/O Module Nest for Relay I/O Modules in the CENTUM CS/VP RIO system. It provides mounting and connectivity for relay input and output modules such as ADM15R (relay input) and ADM55R (relay output). The AMN21 enables the DCS to interface with high-voltage or isolated field devices using electromechanical relay contacts, providing robust galvanic isolation for safety-critical applications.

Key Specifications

• Model: AMN21
• Type: I/O Module Nest for Relay I/O Modules
• Compatible Modules: ADM15R (Relay Input Module), ADM55R (Relay Output Module)
• Power Supply: 5.0 VDC from node interface unit
• Mounting: Node Interface Unit or I/O Expansion Rack

Environmental Specifications

• Operating Temperature: 0°C to +50°C
• Relative Humidity: 5% to 95% RH (non-condensing)
• Storage Temperature: -20°C to +70°C

Installation Guide

1. Mount the AMN21 in the node interface unit or expansion rack.
2. Install relay I/O modules (ADM15R/ADM55R) into the nest slots.
3. Connect field devices to the relay terminals, observing voltage and current ratings.
4. Install suppression devices (diodes, RC snubbers) for inductive loads to protect relay contacts.
5. Verify relay operation and contact status via CENTUM VP diagnostic displays.

FAQ

• Q: What is the contact rating of ADM15R/ADM55R?
  A: Relay contact ratings vary by module; consult ADM15R/ADM55R specifications for voltage and current limits.
• Q: Can relay modules be mixed with digital modules?
  A: No, AMN21 is specifically for relay modules; use AMN31/AMN32 for digital transistor I/O modules.
• Q: Is relay status monitoring available?
  A: Yes, relay module status is monitored by the DCS and alarmed on fault conditions.
• Q: What is the relay response time?
  A: Electromechanical relay response is typically 5–15 ms; solid-state relays offer faster switching if required.

Selection Tips

• Use AMN21 for applications requiring galvanic isolation or high-voltage switching beyond transistor I/O capabilities.
• Specify ADM15R for isolated digital inputs and ADM55R for isolated digital outputs.
• Consider solid-state relays for high-speed switching applications where electromechanical relay life is a concern.