YOKOGAWA PW701 Power Supply Module

The Yokogawa PW701 is a high-capacity Power Supply Module primarily utilized in the CENTUM CS, CENTUM VP, and ProSafe-RS (Safety Instrumented System) architectures.

 It is designed to provide high-current, regulated DC power to the Field Control Station (FCS) backplane, supporting logic circuits, communication modules, and I/O units.

1. Introduction

The PW701 is a critical infrastructure module for Yokogawa's most robust control and safety platforms. 

Unlike the smaller PW441 series, the PW701 is built for high-demand racks, providing a significant output of 29 Amperes at 5.1 V DC. 

Its design emphasizes high reliability and "mission-critical" availability, often found in the ProSafe-RS safety system where fail-safe operation is mandatory to protect personnel and the environment.

2. Technical Parameter Table

High Output Capacity: Delivering 29A, it can power a fully loaded rack of high-density I/O modules that smaller power supplies cannot handle.

ProSafe-RS Compatibility: Engineered with a fail-safe design philosophy, ensuring that a power fault does not lead to an unsafe state in emergency shutdown (ESD) systems.

Redundancy Management: When paired, the modules share the load and feature a "READY" contact output to signal the DCS if one unit loses power or fails.

Advanced Diagnostics: Includes internal monitoring to detect overvoltage, overcurrent, and thermal irregularities.

Industrial Hardening: Built to withstand the harsh conditions of process plants, with high resistance to vibration and wide voltage fluctuations.

4. Application Cases

Emergency Shutdown (ESD) Systems: Providing the main power for ProSafe-RS logic solvers in oil and gas refineries.

Large-Scale DCS Racks: Powering CENTUM VP Field Control Stations that manage a high concentration of communication modules (like Vnet/IP interfaces).

Fire and Gas (F&G) Systems: Ensuring continuous operation of safety sensors and alarm logic in hazardous environments.

High-Density I/O Nodes: Used in remote I/O enclosures where many digital and analog modules are concentrated in a single rack.

5. Related Models & Same Series

The PW70x series is divided based on the local utility power requirements of the plant.

Other Models in the Same Series

PW702: The 220–240 V AC version of this high-capacity module, commonly used in international projects outside North America.

PW704: The 24 V DC input version, used for sites with large battery backup systems or DC bus distribution.

PW301 / PW302: Medium-capacity power modules for smaller node configurations.

Related System Components

CP701 / CP703: CPU modules for the CENTUM CS 3000 series that are often paired with this power supply.

SAI143 / SAI533: ProSafe-RS safety I/O modules that rely on the PW701 for their internal logic power.

AEP9D: Secondary power supply bus units that interface with these modules for expanded distribution.