AND20 Yokogawa Node Interface Unit

Hardware Specifications

DCS Communication and Process Interface Characteristics

The Yokogawa AND20 controls synchronized data transfer between Field Control Stations and connected I/O units through ESB and ER bus communication paths. It manages physical communication timing, node addressing, and diagnostic data exchange between the control processor and remote I/O hardware.

The module supports redundant communication structures to maintain bus availability during hardware faults or maintenance operations. In addition, the AND20 provides status monitoring functions for communication conditions, node operation, and connected I/O unit conditions.

For Yokogawa process control architectures, the interface design supports integration with industrial signal systems using standard process communication methods. The module can operate with distributed I/O structures where analog and digital field signals are collected through CENTUM VP control networks.

Frequently Asked Questions

Q: Does the Yokogawa AND20 support redundant communication configurations?
A: Yes. The AND20 supports redundant ESB or ER bus configurations when installed within compatible Yokogawa CENTUM VP system architectures.

Q: Can the AND20 replace connected I/O modules during system operation?
A: The AND20 supports maintenance procedures within Yokogawa system configurations; however, hot replacement limitations depend on the installed FCS hardware arrangement and system engineering rules.

Q: What type of signals does the AND20 directly process?
A: The AND20 does not directly convert field signals. It manages communication between the control station and connected I/O units that process analog and digital field inputs and outputs.

Field Installation Guidelines

• Install the AND20 in the designated Yokogawa FCS or I/O node mounting location according to system hardware drawings.
• Verify the 24 VDC power input wiring before energizing the module.
• Use approved shielded communication cables for ESB and ER bus connections where required by the system design.
• Separate communication wiring from high-voltage power cables to reduce electromagnetic interference.
• Confirm bus termination, node addressing, and redundancy settings before system startup.
• Check diagnostic indicators after installation to verify communication status and connected I/O unit operation.