NFAI841-S50 | Yokogawa | CENTUM VP 8-Channel High-Precision Analog Input Module

Product Overview

The Yokogawa NFAI841-S50 functions as a high-performance, 8-channel analog input module within the CENTUM VP Distributed Control System (DCS) architecture. This "S50" variant builds upon the high-precision 16-bit A/D conversion of the NFAI841 series by adding enhanced environmental hardening, including ISA Standard G3 conformal coating and an extended operating temperature range. It captures bipolar voltage (±10 V) and current (±20 mA) signals with extreme accuracy, making it the primary choice for mission-critical monitoring in corrosive or non-climate-controlled industrial zones. We supply this unit as 100% Brand New and Original to ensure your system maintains peak reliability in the most demanding conditions.

Part Number Breakdown

The NFAI841-S50 utilizes Yokogawa's suffix logic to identify its specialized environmental protection:

Technical Specifications

The NFAI841-S50 delivers superior signal resolution even under thermal stress.

• Number of Input Channels: 8 independent channels.

• Input Signal Range: ±10 V (Voltage) / ±20 mA (Current).

• A/D Conversion Resolution: 16-bit.

• Input Impedance: 10 MΩ (Voltage input).

• Data Refresh Cycle: 10 ms.

• Operating Temperature: -20 to 70°C (-4 to 158°F).

• Environmental Protection: ISA Standard G3 conformal coating.

• Power Consumption: 2.5 W.

• Condition: Guaranteed 100% Brand New and Original.

Engineering Advantages

The NFAI841-S50 provides targeted technical solutions for extreme-environment DCS integration:

• Corrosion Resistance (ISA G3): The module features a specialized conformal coating that meets ISA Standard G3 requirements. This protection prevents copper corrosion and "silver whiskers" in facilities with high concentrations of Hydrogen Sulfide (H2S), Chlorine, or Sulfur Dioxide, significantly extending hardware lifespan in petrochemical and wastewater plants.

• Superior Thermal Operating Window: Unlike standard I/O modules that cap at 60°C, the NFAI841-S50 operates reliably up to 70°C. This eliminates the need for expensive cabinet cooling systems in hot climates or high-heat process areas, reducing overall infrastructure costs.

• High-Fidelity 16-bit Resolution: The 16-bit A/D converter resolves minute process fluctuations that standard 12-bit modules miss. This granularity provides the precise data required for advanced control strategies, such as fuel-to-air ratio optimization in power generation.

• Minimal Loading Effect: The ultra-high 10 MΩ input impedance ensures the module does not "pull down" the field signal. This maintains the integrity of the measurement even when using low-power transmitters or high-resistance cable runs.

FAQs

• How does the S50 differ from the S00 version?

  The S50 version adds ISA Standard G3 conformal coating and extends the maximum operating temperature to 70°C. While the core electrical specs are identical, the S50 is designed specifically for harsh or corrosive environments.

• Can I mix current and voltage inputs on the same NFAI841-S50?

  Yes. You can configure each channel individually via the CENTUM VP software to accept either voltage or current signals, allowing for maximum flexibility in cabinet wiring.

• What is the benefit of the 10ms refresh cycle?

  The 10ms cycle ensures that the DCS receives fresh data fast enough for high-dynamic control loops, such as those governing turbine speed or rapid pressure relief valves.

• Is this module factory-sealed?

  Absolutely. We supply only 100% Brand New hardware. Every NFAI841-S50 arrives in the original Yokogawa factory box with matching serial numbers and intact manufacturer seals, ensuring zero prior field deployment.