Yokogawa AAI835-S00 CENTUM VP 4-In/4-Out Isolated Analog I/O Module

Product Description

The AAI835-S00 (Part Number: AAI835-S00) is a hybrid signal processing interface designed for Yokogawa’s CENTUM VP and CS 3000 distributed control systems. This module provides a dual-purpose architecture, hosting four dedicated 4 to 20 mA input channels and four dedicated 4 to 20 mA output channels within a single slot. This high-density design is specifically engineered for precision control loops where space optimization and galvanic isolation are paramount.

Every channel on the AAI835-S00 is electrically isolated from the system backplane and from other channels, effectively neutralizing ground loops and protecting the DCS from field-side electrical transients. The module is optimized for real-time responsiveness, featuring a rapid 10 ms update cycle. It supports various field connection methods including pressure clamp terminals and KS cable interfaces, ensuring it can be integrated into diverse cabinet designs with ease.

Detailed Technical Specifications

• Primary Function: Combined Analog Input and Output Module

• Input Configuration: 4 channels, 4 to 20 mA DC (Isolated)

• Output Configuration: 4 channels, 4 to 20 mA DC (Isolated)

• Data Refresh Frequency: 10 ms internal update period

• Input Precision: ±16 μA

• Output Precision: ±48 μA

• Input Resistance (Active): 250 Ω nominal (varies 290–450 Ω based on current)

• Output Load Capability: Supports 0 to 750 Ω resistance

• Open-Circuit Detection: Output current monitoring below 0.65 mA

• Field Power Output: >15.0 V at 20 mA; <29.3 V at 0 mA

• Isolation Rating: 500 V AC dielectric strength for 1 minute

• Thermal Stability: ±16 μA drift per 10°C variation

• Current Consumption: 360 mA @ 5 V DC; 450 mA @ 24 V DC

• Module Mounting: Compatible with ESB/ER bus node units

• Digital Support: HART communication available (via firmware EB401 rev. 2+)

• Physical Mass: 0.3 kg

Module Suffix and Option Code Breakdown

• AAI835: Base model for 4-input/4-output isolated analog I/O

• -S: Standard communication and performance specification

• 0: Non-explosion protected variant for safe area installations

• 0: Basic hardware functional type

Common Industrial Applications

• Integrated Control Loops: Simultaneous sensing of flow rates and positioning of control valves in a single module.

• Space-Constrained Cabinets: Reducing the physical footprint of I/O nests by combining input and output functions.

• Isolated Signal Processing: Facilities with significant ground potential differences requiring channel-to-channel protection.

• Critical Monitoring: High-speed 10ms data acquisition for fast-acting safety instrumented functions.

Frequently Asked Questions

Does this module support smart field devices?

Yes, the AAI835-S00 supports digital communication via the HART protocol when paired with appropriate firmware (EB401 rev. 2 or later). This allows for diagnostic pass-through from smart transmitters and positioners.

What happens if a field wire is disconnected?

The module features built-in open-circuit detection for the output side. If the loop current drops below 0.65 mA, the system will flag a diagnostic error to alert operators of the cable failure.

Can it power 2-wire transmitters?

The AAI835-S00 provides a built-in transmitter power supply capable of delivering at least 15V at full 20mA load, making it suitable for standard 2-wire loop-powered instruments.