Product Overview
The Yokogawa AAI835-H00 is an advanced 8-channel isolated analog input/output module. Engineered specifically for Yokogawa Centum VP distributed control systems, this module handles 4-channel analog inputs and 4-channel analog outputs concurrently. It processes standard 4 to 20 mA loop currents with full channel-to-channel isolation. This hardware level prevents common-mode noise propagation in dirty electrical environments.
The module features built-in digital communication supporting the HART protocol. This enables direct access to field instrument variables and diagnostics. It uses a high-speed data update cycle of 10 ms to satisfy critical control loops. To request a quick quote, email our sales desk at info@oiltechcontrols.com or connect instantly via WhatsApp at +86 158 8020 0923.
Configuration Breakdown & Suffix Codes
The model code structure for the AAI835 series determines the exact hardware build and certification standard:
- AAI835 — Analog I/O Module (4 to 20 mA, 4-Channel Input / 4-Channel Output, Isolated)
- ├── -H — Communication Type: With digital communication (HART protocol)
- ├── 5 — Safety / Protection: Non-explosion protection specification
- └── 0 — Design Indicator: Basic Type (Standard hardware revision H00)
| System Component Category | Compatible Model Codes |
|---|---|
| Input/Output Card Options | Single-unit mount: ATI3S / Dual-redundant configuration: ATI3D |
| Signal Converters / Adapters | Screw Terminal Adapter: ATK4A / Spring Terminal Adapter: ATB3A |
| System Interconnection Cable | Dedicated interface cable: KS1 |
| Compatible Terminal Boards | Standard analog board: AEA4D / HART passthrough board: AEA3D |
Technical Specifications
| Parameter | Engineering Specification |
|---|---|
| Model Code | AAI835-H00 |
| Channel Isolation | Fully isolated channel-to-channel and channel-to-system |
| Withstand Voltage | 500 V AC for 1 minute (tested between all circuits) |
| Input Circuit Resistance | Power ON: 290 Ω to 450 Ω / Power OFF: 500 kΩ minimum |
| Allowable Load Resistance | 0 to 750 Ω (output loop limit) |
| Calibration Accuracy | Input: ±16 µA / Output: ±48 µA |
| Transmitter Loop Power | 15.0 V DC minimum (at 20 mA) up to 29.3 V DC (at 0 mA) |
| Thermal Drift Coefficient | ±16 µA per 10 degrees Celsius fluctuation |
| System Power Demand | 360 mA max at 5 V DC; 450 mA max at 24 V DC |
| Weight | Approximately 0.30 kg |
Oiltech Controls Limited’s Insight
The AAI835-H00 represents a highly efficient hybrid architecture. By combining 4 analog inputs and 4 analog outputs onto a single high-density card, system engineers can optimize slot usage in node units. This dual-purpose design reduces space requirements by 50% compared to dedicated input and output cards. The HART protocol support avoids the cost of external multiplexers. This card provides raw sensor data and loop health diagnostics directly to Centum VP controllers.
Packaging, Shipping & Warranty
- Package Includes: Factory-sealed Yokogawa AAI835-H00 module, functional test report, and terminal mounting guide.
- Warranty Terms: Covered by a comprehensive 12-month industrial functional warranty.
- Global Delivery Logistics: Shipped worldwide using premium air freight providers, including FedEx, UPS, and DHL.
Frequently Asked Questions (FAQ)
1. How does the AAI835-H00 handle high input impedance when field transmitters are powered off?
When the system is powered off, the input resistance increases to 500 kΩ or larger. This high resistance stops unintended loop currents and protects system power supplies from overloading during maintenance.
2. Can we mix active (4-wire) and passive (2-wire) transmitters on the same module?
Yes. However, because the module provides up to 29.3 V DC on the loop, external barriers or custom terminal board jumpers (using the ATK4A adapter) must be configured. This isolates external transmitter power sources from the card’s internal power supply.
3. How does this card perform under high ambient temperature fluctuations?
The card features low thermal drift, rated at ±16 µA per 10°C. This ensures stable instrument readings even when deployed in outdoor field junction boxes or high-temperature rack rooms.
4. Does the HART functionality introduce any latency into the analog 10 ms update cycle?
No. The HART digital FSK signal is modulated on top of the 4 to 20 mA analog signal. The module processes the digital communications in a secondary microprocessor. This guarantees that the critical analog control loop remains constant at its 10 ms update interval.
5. What is the best strategy for upgrading legacy non-HART modules to the AAI835-H00?
Confirm that your existing backplane uses the AEA4D or AEA3D terminal boards and that the KS1 system cable is intact. Upgrading the system software to recognize the new HART suffix code activates diagnostic variables without requiring physical changes to the terminal blocks.
For more information, feel free to contact us.
Contact Information Inquiries: info@oiltechcontrols.com, +86 158 8020 0923
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