Yokogawa ATK4A-00 Rack-mounted terminal block

The Yokogawa ATK4A-00 is a specialized Terminal Block (also categorized as a connection unit) primarily used within the CENTUM VP and CENTUM CS 3000 Distributed Control Systems. It serves as the physical interface between field wiring and the system’s I/O modules.

1. Introduction

The ATK4A-00 is a 19-inch rack-mountable terminal block designed to facilitate the connection of signal cables.

It acts as a “bridge,” allowing field signals (such as 4-20mA loops or digital contacts) to be organized and then sent to I/O modules via specialized signal cables (like the KS1 or KS2 series). Its robust design ensures that field connections remain secure and manageable, even in high-density wiring cabinets.

2. Technical Parameter Table

3. Related Models

The ATK4A-00 is often part of a broader assembly involving signal conditioning and distribution:

ATK4A-10: A variant that may include different terminal markings or minor hardware revisions.

KS1 / KS2 Cables: The multi-core cables that plug into the back of the ATK4A to carry signals to the I/O cards.

AAB841 / AAI143: Analog I/O modules that typically receive signals routed through this terminal block.

ATP series: Other terminal units designed for different signal types (e.g., thermocouple-specific terminals).

4. Product Advantages and Features

High-Density Wiring: Consolidates multiple field signals into a single standardized interface, saving space in control cabinets.

M4 Screw Security: Uses heavy-duty M4 screw terminals, which provide superior vibration resistance and electrical contact compared to smaller spring-clamp systems.

Ease of Maintenance: Individual terminals are clearly numbered, allowing for easy troubleshooting and signal tracing without disconnecting the main I/O card.

Passive Design: As a passive component, it does not require an external power supply and has an extremely high Mean Time Between Failures (MTBF).

5. Application Cases

Petrochemical Cabinets: Used to terminate hundreds of analog flow and pressure transmitter signals before they enter the DCS processors.

Power Plant Marshaling: Acts as a marshaling point for various motor status signals and valve position feedbacks.

Retrofit Projects: Used when replacing legacy systems, allowing old field wiring to be landed on a new, organized terminal structure before connecting to modern CENTUM VP I/O.

6. Other Models in the Same Series

Yokogawa provides several versions of terminal blocks depending on the signal type and the required connector interface:

ATM Series: Specifically designed for pulse and digital signals with higher isolation requirements.

ATE Series: Optimized for thermocouple inputs, featuring cold-junction compensation (CJC) mounting capabilities.

ATD Series: Specialized for digital I/O distribution with LED indicators for signal status.