The Honeywell 51204172-125 is a Fail-Typically-Active (FTA) analog output module designed for integration with Honeywell’s Universal Control Network (UCN) architecture, commonly used in distributed control systems (DCS) such as TDC 3000 and Experion PKS. Unlike its HLAI (High-Level Analog Input) counterparts, this module focuses on output signal transmission, converting digital control signals from the DCS into analog outputs (e.g., 4–20 mA, 0–10 V) to drive field devices like valves, actuators, or variable-speed drives .
Key to its design is safety-critical operation, where the FTA mechanism ensures outputs default to a preconfigured safe state (e.g., fully closed valve) during faults, aligning with IEC 61508 SIL 2 requirements. The module supports Modbus RTU communication for diagnostic purposes and features 2.5 kV galvanic isolation to protect against electrical noise and voltage spikes in harsh industrial environments .
Signal Output:
- 8-channel analog output with configurable ranges (4–20 mA, 0–10 V) for precise control of process actuators.
- High resolution: 16-bit DAC with ±0.1% accuracy (at 25°C) for stable signal transmission.
- Output fail-safe modes: Programmable to hold last valid value, go to zero, or follow a predefined safe state during faults.
Safety & Reliability:
- FTA design: Ensures outputs fail to a safe state during module malfunctions, critical for applications like emergency shutdown (ESD) systems.
- Dual redundancy support: Optional redundant power supplies and communication paths for mission-critical processes.
- IP65 environmental protection: Dust-tight and water-resistant housing for operation in extreme conditions (e.g., oil refineries, chemical plants) .
Communication:
- UCN network integration: Communicates with Honeywell controllers (e.g., C200, C300) via UCN at 1 Mbps for real-time control.
- Diagnostic interface: RS-485 port for remote troubleshooting and firmware updates using Honeywell Engineering Workstation software.
Configuration:
- Programmable via Honeywell software: Supports channel-level parameterization (e.g., signal scaling, fail-safe behavior) and real-time status monitoring.
- LED indicators: Provide visual feedback for power, fault status, and channel activity .
| Parameter | Description |
|---|
| Output Channels | 8 analog outputs (4–20 mA, 0–10 V) |
| Output Accuracy | ±0.1% of full scale (25°C) |
| Resolution | 16-bit DAC |
| Signal Isolation | 2.5 kV galvanic isolation |
| Communication | UCN (1 Mbps); RS-485 diagnostic port |
| Power Supply | 24 VDC ±10% (1.5 A max), redundant inputs supported |
| Operating Temperature | -40°C to +70°C (operation); -40°C to +85°C (storage) |
| Certifications | CE, UL, CSA, IEC 61508 SIL 2 (estimated) |
| Physical Dimensions | 120 mm × 80 mm × 30 mm (rack-mounted) |
| Weight | 0.4 kg (0.88 lbs) |
Modular Architecture:
- Rack-mounted in Honeywell UCN I/O chassis, supporting up to 8 modules per rack for scalable I/O expansion.
- Hot-swappable: Allows module replacement without system shutdown, minimizing maintenance downtime.
Redundancy & Fault Tolerance:
- Built-in self-test (BIST) with diagnostic alerts for open circuits, short circuits, or signal drift.
- Optional dual power supplies and communication paths for fault-tolerant operation .
Industrial Compliance:
- Designed for shock (50 G peak) and vibration (2.5 G RMS) resistance, compliant with IEC 60068-2 standards.
- Extended temperature range (-40°C to +70°C) for extreme industrial environments .
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