Introduction
The Yokogawa NFAI835-S50 Analog Input/Output Module is a compact hybrid I/O solution designed for STARDOM FCN/FCJ distributed control systems (DCS). It integrates both analog signal acquisition and analog signal output within a single industrial module, enabling efficient process monitoring and closed-loop control in automation environments.
This module is engineered for 4–20 mA industrial signal handling, delivering stable conversion between field instruments and control systems. With isolated channels and a rugged industrial design, it is widely used in continuous process industries where accuracy, reliability, and long-term stability are essential.
Technical Specifications
| Parameter | Specification |
|---|
| Model | NFAI835-S50 |
| Manufacturer | Yokogawa |
| Type | Analog Input / Output Module |
| I/O Configuration | 4 AI / 4 AO (isolated channels) |
| Input Signal | 4–20 mA DC |
| Output Signal | 4–20 mA DC |
| Resolution | 16-bit A/D & D/A |
| Accuracy | ±0.1% of full scale |
| Data Refresh Cycle | 10 ms |
| Step Response Time | ~100 ms |
| Isolation | Channel-to-system and channel-to-channel isolation |
| Input Resistance | 250 Ω (powered), ≥500 kΩ (unpowered) |
| Load Resistance (Output) | 0–750 Ω |
| Transmitter Supply | 20.2–29.3 V DC |
| Overcurrent Protection | Supported |
| Operating Temperature | 0°C to +55°C / industrial variant up to +60°C range |
| Storage Temperature | -20°C to +70°C |
| Humidity | 5–95% RH non-condensing |
| Dimensions | ~150 × 90 × 50 mm |
| Weight | ~0.6 kg |
| Mounting Type | Rack / FCN base unit system |
Applications
The NFAI835-S50 is designed for integrated process control environments where both measurement and actuation are required.
Typical applications include:
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Oil & gas production monitoring and control systems
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Petrochemical and refinery automation loops
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Power generation plant control systems
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Water and wastewater treatment facilities
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SCADA and DCS distributed control architectures
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Industrial valve and actuator control systems
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Compressor and pump regulation systems
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Manufacturing process automation
Its hybrid I/O structure reduces system complexity while improving control efficiency.
Advantages
The Yokogawa NFAI835-S50 delivers strong industrial performance benefits:
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Hybrid 4 AI / 4 AO design reduces cabinet space and wiring cost
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High-resolution 16-bit processing ensures precise signal handling
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Fast 10 ms refresh cycle supports real-time control
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Fully isolated channels improve noise immunity and system safety
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Stable 4–20 mA compatibility for universal industrial integration
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Compact modular structure simplifies system expansion
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Reliable long-term operation in continuous-duty environments
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Seamless integration with Yokogawa DCS systems
Technical FAQs
1. What is the main function of the NFAI835-S50?
It provides both analog input and output functions in a single module.
2. How many channels does it support?
It supports 4 analog inputs and 4 analog outputs.
3. What signal type does it use?
Standard 4–20 mA DC industrial signals.
4. Is the module isolated?
Yes, it features channel-to-channel and system isolation.
5. What is the accuracy level?
Approximately ±0.1% of full scale.
6. What is the response time?
Around 100 ms step response time.
7. What is the data refresh cycle?
Approximately 10 ms.
8. What is the operating temperature range?
0°C to +55°C (industrial environment dependent).
9. What is the weight of the module?
Approximately 0.6 kg.
10. What systems is it compatible with?
Yokogawa STARDOM FCN/FCJ distributed control systems.
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