Yokogawa AAI835-H00 S1 4–20 mA HART Analog Input Output Module, Isolated Channels

Brand YOKOGAWA

Model Yokogawa AAI835-H00 S1 4 20

Product Overview

The Yokogawa AAI835-H00 S1 is an isolated 4–20 mA analog input/output module in Yokogawa’s FIO (Field I/O) family, designed for installation in CENTUM VP and CENTUM CS 3000 field control stations, ESB bus node units and optical ESB bus node units. It provides four current input channels and four current output channels in a single slot, letting one module both acquire transmitter signals from the field and drive control outputs such as valve positioners and I/P converters. In the DCS architecture the Yokogawa AAI835-H00 S1 functions as a signal converter: field analog values are converted to internal data for the field control station, while the FCS’s internal data is converted back to analog current for output devices.

The module is built around fully isolated channels — each channel is isolated from the system side and from the other channels. That isolation is what makes the Yokogawa AAI835-H00 S1 suitable for plants where transmitter loop grounds, motor drives and long cable runs would otherwise introduce ground loops and common-mode noise. The H suffix denotes integrated HART communication: without a separate HART modem card, the module can carry the digital HART signal superimposed on the 4–20 mA loop, giving access to device diagnostics, ranging and calibration data from smart transmitters and positioners.

Positioned as a maintenance, retrofit and expansion component for established CENTUM systems, the AAI835-H00 S1 is a compact way to keep existing analog loops running without re-engineering the I/O cabinet. Its 10 ms data update period supports responsive control-loop processing, while channel-to-system and channel-to-channel withstand voltage of 500 V AC for one minute strengthens signal integrity in electrically demanding environments. For plants running mixed acquisition and actuation on the same skid, a 4-in/4-out arrangement also saves slots and reduces wiring compared with separate input and output modules.

Product Overview

Positioned as a maintenance, retrofit and expansion component for established CENTUM systems, the is a compact way to keep existing analog loops running without re-engineering the I/O cabinet. Its 10 ms data update period supports responsive control-loop processing, while channel-to-system and channel-to-channel withstand voltage of 500 V AC for one minute strengthens signal integrity in electrically demanding environments. For plants running mixed acquisition and actuation on the same skid, a 4-in/4-out arrangement also saves slots and reduces wiring compared with separate input and output modules.

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Description

Technical Specifications

Parameter	Value
Product Model	AAI835-H00 S1
Manufacturer	Yokogawa Electric Corporation
Product Type	Analog I/O module (current I/O, isolated channels)
Platform	CENTUM VP / CENTUM CS 3000 FIO
Input channels	4 (isolated), 4–20 mA DC
Output channels	4 (isolated), 4–20 mA DC
Allowable input current	25 mA
Input resistance, power ON	290 Ω at 20 mA / 450 Ω at 4 mA
Input resistance, power OFF	500 kΩ or higher
Allowable output load resistance	0 to 750 Ω
Load resistance at 60–70 °C	200 to 750 Ω
Open-circuit detection	Less than 0.65 mA
Accuracy	Input ±16 µA; output ±48 µA
Data update period	10 ms
Transmitter supply	15.0 V or higher at 20 mA; 29.3 V or less at 0 mA
Temperature drift	±16 µA / 10 °C
Withstanding voltage	500 V AC for 1 minute (I/O to system, and between I/O channels)
Current consumption	5 V DC: 360 mA max.; 24 V DC: 450 mA max.
HART communication	Available (built-in HART modem)
Weight	Approx. 0.30 kg
External connection	Pressure clamp terminal, MIL connector cable, dedicated KS1 cable

Main Features and Advantages

Combined acquisition and control in one module

The Yokogawa AAI835-H00 S1 packages four analog inputs and four analog outputs in a single FIO slot. For a small process area or a single skid, that is often the whole analog requirement: pressure, flow, level and temperature transmitters feed the inputs, while four current-driven actuators receive the outputs. Consolidating acquisition and control on one module reduces the number of cards in the node, shortens wiring and keeps spare-part holdings simpler.

Full channel isolation

Every channel on the Yokogawa AAI835-H00 S1 is isolated from the system side and from the other channels. The rated withstand voltage is 500 V AC for one minute. In practical terms this suppresses ground loops and protects the FCS backplane from field-side transients — the kind of interference that otherwise appears as drift, unstable readings or nuisance alarms. For plants with mixed power systems, cathodic protection or long field runs, this is the specification that matters most.

HART without a separate modem card

The H in AAI835-H00 S1 means HART communication is built in. Smart HART devices can be configured, ranged and diagnosed over the same 4–20 mA wiring already connected to the module, so there is no need to add a dedicated HART card or break the loop for routine device management. This shortens commissioning and makes condition-based maintenance practical.

Precision and update speed suited to control loops

With input accuracy of ±16 µA, output accuracy of ±48 µA and a 10 ms data update period, the Yokogawa AAI835-H00 S1 delivers the combination of precision and responsiveness expected of a process control I/O card. The built-in open-circuit detection below 0.65 mA also helps distinguish a broken loop from a genuine process condition, so fault finding starts from the right place.

Redundancy-ready

The module supports dual-redundant configuration when installed with the appropriate dual pressure-clamp terminal board, so a failed I/O channel or wiring assembly need not take the loop out of service. That makes the Yokogawa AAI835-H00 S1 appropriate for critical control loops where availability is designed in rather than added later.