Yokogawa AAI835-S50 | Analog I/O Module | 4-Channel Input / 4-Channel Output

Technical Product Overview

The AAI835-S50 is a high-performance, isolated Analog I/O module designed for integration within Yokogawa’s CENTUM VP and ProSafe-RS control systems. This hybrid module provides a space-efficient solution by combining four channels of analog input and four channels of analog output into a single slot, making it ideal for localized control loops where both sensing and actuation are required.

As a standard, non-explosion-protected variant, the AAI835-S50 utilizes full channel-to-channel isolation. This electrical separation prevents ground loop interference and protects the system's internal 5V and 24V DC rails from field-side transients. The module supports 4-20 mA signaling for both input and output stages, ensuring compatibility with a vast range of industrial transmitters and valve positioners.

Detailed Engineering Specifications

• I/O Configuration: 4-Channel Input and 4-Channel Output (Combined)

• Signal Range: 4 to 20 mA DC (Both Input and Output)

• Isolation Architecture: Fully isolated channels (Channel-to-Channel and Channel-to-System)

• Model Configuration: AAI835-S50 (Standard, Basic Type, No Explosion Protection)

• Current Consumption (Internal): 360 mA @ 5 VDC

• Current Consumption (Field/Load): 450 mA @ 24 VDC

• External Interface Options: Pressure clamp terminals, MIL connector, or dedicated KS1 cable

• Physical Dimensions: 13.0 cm (H) x 3.3 cm (W) x 10.7 cm (L)

• Module Weight: 0.3 kg (0.66 lbs)

• Mounting Integration: Compatible with Yokogawa I/O units and field control stations

Hardware Connectivity and Reliability

The AAI835-S50 is engineered for high-availability environments. The support for multiple connection types—ranging from traditional pressure clamps to high-density MIL connectors—allows for flexible cabinet internal wiring. For mission-critical applications, the module's 24V DC field-side power management ensures stable loop power even under maximum load conditions across all eight channels simultaneously.

Frequently Asked Questions

Does the AAI835-S50 support HART communication?

Standard AAI835-S50 modules primarily handle 4-20 mA analog signals. If HART digital overlay communication is required for device diagnostics, the HART-compatible version (typically designated with a different suffix) should be verified for your specific system revision.

What is the benefit of isolated channels in this module?

Isolation in the AAI835-S50 ensures that a fault or short circuit on one field loop does not propagate to the other seven channels or the central processor, significantly increasing the fault tolerance of the control loop.