Yokogawa AAI135-H50 Analog Input Module | 8-Ch, HART, Isolated

AAI135-H50 | Yokogawa Analog Input Module (Current Input)

AAI135-H50 is a high-performance analog input module from Yokogawa. It receives 4 to 20 mA signals from field instruments. Each of the 8 channels is fully isolated from the system and from each other. This design eliminates ground loops and protects against surges. The module supports HART digital communication for smart device integration. It also works in dual-redundant configurations for critical loops.

Technical Specifications (At a Glance)

• Brand: Yokogawa
• Model: AAI135-H50
• Type: Analog Input Module (Current Input)
• Channels: 8 isolated inputs
• Signal: 4 to 20 mA (HART compatible)
• Allowable input current: 25 mA max
• Input resistance (Power ON): 290 Ω (20 mA) to 450 Ω (4 mA)
• Input resistance (Power OFF): ≥500 kΩ
• Accuracy: ±16 µA (high precision)
• Weight: 0.3 kg (lightweight for high-density mounting)

Isolation & Withstand Voltage

• Between input and system: 500 V AC for 1 minute
• Between input channels: 500 V AC for 1 minute (channel-to-channel isolation)
• This ensures safety and signal integrity in noisy industrial environments.

Model Code Breakdown

• AAI135 – Analog Input Module, 4-20 mA, 8-channel, isolated
• H – With HART digital communication
• 5 – No explosion protection (standard industrial)
• 0 – Basic type (no special coating)

Dual-Redundancy & System Compatibility

• Supports dual-redundant configuration for fail-safe operations.
• Compatible with Yokogawa CENTUM VP, CS 3000, and ProSafe-RS.
• Works with HART-enabled transmitters (pressure, temperature, flow).
• Also suitable for Modicon Quantum systems via appropriate backplane adapters.

Oiltech Controls Insight

• From our field experience, the AAI135-H50 excels in refinery and chemical applications.
• Its channel-to-channel isolation prevents a single faulty device from affecting others.
• We recommend this module for SIL2/SIL3 loops when used with a safety-certified system.
• For HART communication, use a dedicated HART multiplexer or the host system’s built-in HART capability.
• Always verify the input resistance – it affects the loop power budget, especially with long cables.

Why Buy From Oiltech Controls?

• 15+ years of expertise in industrial automation spares – we know your plant’s needs.
• Global shipping – express delivery via FedEx, UPS, or DHL (24-28 hours dispatch).
• Pre-tested surplus/refurbished units – each module is verified on a test rack.
• 12-month warranty – covers defects and provides technical support.
• Technical pre-check – we confirm firmware revision and HART compatibility before shipping.
• Support for obsolete systems – we supply hard-to-find Yokogawa and Modicon parts.

Expert FAQ (Based on Real Customer Queries)

Q1: Can I mix HART and non-HART transmitters on the same module?
Yes, but you must disable HART on channels connected to non-HART devices via software. Otherwise, the module may report communication errors.

Q2: What is the maximum cable length for 4-20 mA with HART?
For standard twisted-pair cable, keep length under 3000 meters (approx. 9800 ft) to maintain HART signal integrity. For longer runs, use a repeater.

Q3: How do I choose between AAI135-H50 and AAI135-S50?
The H50 includes HART communication; the S50 does not. If you use smart transmitters, choose H50. If you use conventional analog devices, S50 saves cost.

Q4: Is the module hot-swappable in a running system?
Yes, but only if the system supports hot-swap (CENTUM VP does). Always confirm with your system engineer – some older systems require a shutdown.

Q5: What happens if one channel fails?
Only that channel is affected. The other 7 channels continue working normally due to full isolation. Replace the module during scheduled maintenance.

Shipping & Warranty

• Dispatch: Within 24-28 hours after order confirmation.
• Carriers: FedEx, UPS, or DHL (tracking provided).
• Warranty: 12 months against manufacturing defects.
• Technical support is available via email or WhatsApp.

Contact & Support

For inquiries, email info@oiltechcontrols.com or message via WhatsApp +86 158 8020 0923.

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