NFAI835-S50 | Yokogawa| ProSafe-RS Analog Input/Output Module

Product Overview

The Yokogawa NFAI835-S50 serves as a high-performance, combined analog interface for the ProSafe-RS safety instrumented system. This versatile module integrates 4-channel inputs and 4-channel outputs within a single hardware footprint, managing critical 4 to 20 mA signals for both monitoring and control loops. We supply this unit as 100% Brand New and Original, ensuring absolute signal fidelity and compliance with the stringent safety requirements of global industrial process facilities.

Part Number Breakdown

Technical Specifications

Engineering Advantages

• Optimized Hardware Density: By combining four inputs and four outputs on a single module, the NFAI835-S50 effectively halves the required rack space for standard control loops. This high-density architecture simplifies cabinet layouts and reduces the overall system footprint in crowded technical rooms.

• Superior Galvanic Isolation: The module provides 500 V AC isolation between all channels and between the I/O circuitry and the system backplane. This protects the safety controller from ground loops and prevents electrical noise from propagating across the bus, a critical requirement for maintaining SIL3 integrity.

• Comprehensive Diagnostic Coverage: Integrated circuit-open detection triggers at 0.65 mA or less, allowing the system to identify broken wire faults immediately. Furthermore, overcurrent protection safeguards the hardware against field wiring errors or transmitter failures.

• Deterministic Response Timing: A 10 ms data refresh cycle combined with 100 ms step response times ensures the ProSafe-RS system reacts to process deviations with the speed required for emergency shutdown (ESD) and fire and gas (F&G) applications.

FAQs

• Does the NFAI835-S50 provide power to field transmitters? Yes. The module includes a transmitter power supply ranging from 20.2 to 29.3 V DC. It effectively powers 2-wire transmitters directly, eliminating the need for external power distribution blocks for these channels.

• How does the module handle a processor failure? The "Output Fallback" feature allows engineers to pre-set a safe state for each output channel. In the event of a communication loss or processor fault, each channel independently reverts to its designated fallback value (e.g., 4mA or 0mA) to ensure process safety.

• What type of field connection hardware does it support? The module supports both pressure clamp terminals for direct field wiring and MIL connector cables for centralized marshalling. This flexibility allows for rapid deployment in both new builds and legacy system upgrades.

• Is this module suitable for high-temperature environments? The NFAI835-S50 features a maximum temperature drift of only $\pm 0.01\%/^\circ\text{C}$. This stability ensures high accuracy across the standard operating temperature range, even in cabinets subject to minor thermal fluctuations.