Product Overview

The Yokogawa CP345 serves as the primary intelligence hub for the CENTUM CS 3000 Distributed Control System (DCS). This high-speed central processing unit (CPU) executes complex control algorithms and manages real-time data synchronization across the control station. In large-scale industrial operations—such as LNG terminals, continuous chemical processing, and sophisticated power grids—the CP345 maintains the precise timing and logic execution necessary to stabilize volatile processes. Its architecture prioritizes deterministic processing, ensuring that safety-critical control loops and high-frequency data sampling occur without jitter or latency. By integrating robust computational power with advanced fault-tolerance mechanisms, the CP345 safeguards plant productivity and provides the reliable decision-making core required for modern automated infrastructures.

Technical Configuration

The CP345 incorporates a specialized hardware architecture designed to withstand the rigors of 24/7 industrial operation while maintaining extreme logic density:

Dual-Redundant Capability

This CPU module supports high-availability paired configurations. In a redundant setup, two CP345 modules operate in parallel, with the "standby" unit maintaining a mirrored state of the "active" unit's memory. This design enables instantaneous bumpless failover, preventing process upsets if a hardware fault occurs.

Advanced Memory Management

The module features high-speed ECC (Error Correction Code) memory to detect and correct single-bit errors in real-time. This prevents data corruption in environments with high electromagnetic noise, ensuring the integrity of the control logic and historical data buffers.

Vnet Communication Integration

The CP345 communicates via the high-speed Vnet (or VL net), allowing it to interface seamlessly with I/O modules and Human Interface Stations (HIS). It manages large-scale tag databases and complex sequence tables with high-efficiency throughput.

Technical Specifications

Engineering Advantages

The CP345 excels in environments where unplanned downtime is financially catastrophic. Its fanless design relies on high-efficiency heat dissipation through its structural chassis, eliminating a common point of mechanical failure found in commercial-grade computers. The module's internal circuitry features a conformal coating that resists the corrosive effects of airborne chemical contaminants often found in refineries. Furthermore, the CP345 offers backward compatibility with several legacy Yokogawa hardware nests, providing a cost-effective path for upgrading older control stations to modern performance standards without a complete system overhaul.

Installation Guide

When installing the CP345, ensure the module is inserted into the dedicated CPU slot of the Field Control Station (FCS) base plate. Tighten the top and bottom mounting screws to provide a secure mechanical bond and a reliable electrical ground.

Before powering the system, verify that the station address settings on the module's dip switches match the project configuration. For redundant systems, both CP345 modules must have identical hardware revisions and firmware versions to facilitate proper synchronization. We recommend maintaining a clean, dust-free environment with stable humidity levels to prevent electrostatic discharge (ESD) during maintenance. If replacing a module in an active system, follow the "Maintenance Override" procedures in the CENTUM software to ensure a smooth transition to the redundant partner.

Technical FAQs

Q1: What is the main difference between CP345 and the newer CP451?

A1: The CP345 is primarily designed for the CS 3000 series using Vnet communication, while the CP451 is built for the CENTUM VP architecture and utilizes Vnet/IP. The CP345 remains the standard choice for maintaining and expanding existing CS 3000 systems.

Q2: Can the CP345 be hot-swapped during operation?

A2: Yes, in a redundant configuration, you can replace a faulty CP345 while the partner module is "Active" without stopping the controller. The system will automatically synchronize the new module once it is inserted.

Q3: Does this module require a battery for memory retention?

A3: The CP345 utilizes a battery backup for its SRAM to retain user programs and data during a total power loss. We recommend checking and replacing this battery during scheduled annual maintenance to prevent data loss.

Q4: What do the "HRDY" and "CTRL" LEDs indicate?

A4: The HRDY (Hardware Ready) LED indicates that the CPU's internal diagnostics have passed. The CTRL (Control) LED indicates that the module is currently in charge of the control logic and communicating with the I/O modules.