AAI135-H00/K4A00 | Yokogawa | Analog Input Module

Product Overview

The AAI135-H00/K4A00 is a current-input analog acquisition module engineered for Yokogawa CENTUM distributed control systems. It accepts industry-standard 4–20 mA signals from field instruments and delivers stable, high-integrity data to field control stations. With channel-to-channel isolation and optional HART digital communication, the module is suited for precise measurement tasks in continuous process environments.

Electrical and Functional Description

Designed for reliable signal capture, the AAI135-H00/K4A00 focuses on accuracy, electrical isolation, and predictable behavior during both powered and unpowered states. Each input channel is isolated to minimize noise coupling and ground loop effects, which is critical in dense control cabinets and long cable runs.

The H-suffix enables HART protocol pass-through, allowing simultaneous analog measurement and device diagnostics over the same wiring.

Technical Specifications

• Model designation: AAI135-H00/K4A00
• Module category: Analog input, current type
• Input signal range: 4 to 20 mA
• Number of input channels: 8 isolated channels
• Allowable input current: Up to 25 mA
• Measurement accuracy: ±16 µA
• Input resistance (power ON):
  • Approx. 290 Ω at 20 mA
  • Approx. 450 Ω at 4 mA
• Input resistance (power OFF): ≥ 500 kΩ
• Withstanding voltage:
  • Input to system: 500 V AC for 1 minute
  • Between input channels: 500 V AC for 1 minute
• Digital communication: HART protocol supported
• Dimensions: 107.5 × 32.8 × 130 mm
• Weight: 0.3 kg

System Integration and Options

This module is intended for use within Yokogawa CENTUM architectures. The /K4A00 option includes a KS cable interface adapter (ATK4A-00), simplifying wiring and ensuring compatibility with designated terminal and cabling solutions.

Typical Applications

Common use cases for the AAI135-H00/K4A00 include:

• Process variable acquisition from pressure, flow, level, and temperature transmitters
• HART-enabled device monitoring and configuration
• Analog measurement in power generation, refining, chemical processing, and utilities

Frequently Asked Questions

How many input channels does this module provide? The AAI135-H00/K4A00 provides eight analog input channels, each with electrical isolation.

Does the module support HART communication? Yes. The H suffix indicates built-in support for HART digital communication alongside the 4–20 mA signal.

Is this module suitable for high-noise environments? Yes. Channel-to-channel and input-to-system isolation significantly reduce interference from electrical noise.