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Product Introduction
The Yokogawa NFAI135 Analog Input Module is a high-performance analog signal acquisition unit designed for integration with ProSafe-RS Safety Instrumented Systems (SIS). It plays a crucial role in gathering and converting field analog signals into digital form for monitoring and control purposes in safety-critical applications.
This module supports multiple channels and is engineered to deliver high accuracy, noise immunity, and fault tolerance, making it suitable for demanding industrial environments such as oil & gas refineries, petrochemical complexes, and power stations. It meets stringent safety and reliability standards (including SIL compliance), enabling it to be used confidently in safety layers of plant automation architecture.
Designed to interface seamlessly with the SCS (Safety Control Station) in Yokogawa’s ProSafe-RS platform, the NFAI135 offers redundant connection support, diagnostic capabilities, and easy field termination, making it a cornerstone in the design of safety-integrated process control systems.
Technical Specifications
| Parameter | Details |
|---|---|
| Model | NFAI135 |
| Function | Analog Input Module for Safety Systems (SIS) |
| System Compatibility | Yokogawa ProSafe-RS |
| Number of Channels | 16 analog input channels |
| Input Signal Type | 4–20 mA DC (standard), other ranges configurable |
| Input Type | Single-ended or differential |
| Input Impedance | ≥250 Ω |
| Resolution | 16-bit A/D conversion |
| Accuracy | ±0.1% of span |
| Sampling Rate | 100 ms (typical) |
| Isolation | Channel-to-bus and channel-to-channel isolation |
| Self-Diagnostics | Open circuit detection, out-of-range detection |
| Redundancy Support | Yes (with SCS redundancy configuration) |
| Operating Temperature | 0 to 55°C |
| Storage Temperature | -20 to 70°C |
| Humidity Range | 5% to 95% RH (non-condensing) |
| Mounting Method | Mounted on SCS base unit |
| Material | Flame-retardant engineering plastic |
| Power Supply | Supplied via backplane from SCS |
| Dimensions (W × H × D) | 130 x 107.5 x 32.8 mm |
| Weight | 0.3 kg |
| Certifications | CE, ATEX, SIL3, RoHS, CSA, UL |
Applications
The NFAI135 Analog Input Module is specifically designed for safety applications where reliable signal acquisition and system diagnostics are critical. It is widely adopted in:
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Oil & Gas Refining – For pressure, temperature, and flow monitoring in hazardous areas.
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Petrochemical Plants – Collects analog data from safety valves, emergency shutdown sensors, and process analyzers.
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Power Generation – Gathers analog input from turbines, boilers, and auxiliary safety systems.
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Pharmaceutical Industry – Ensures critical temperature and pressure inputs are safely acquired in GxP environments.
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LNG and Chemical Storage – Used in SIS architectures to monitor tank levels and leak detection systems.
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Offshore Platforms – Ideal for high-integrity safety system input acquisition in extreme conditions.
Product Advantages
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Certified for Safety: Fully compliant with SIL3 (IEC 61508), suitable for the most demanding safety functions.
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High Accuracy and Stability: 16-bit resolution with low drift ensures precision over long operational periods.
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Full Diagnostics: Built-in open-loop and range-check diagnostics allow proactive fault identification.
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Compact Design: Slim module width enables dense installation within ProSafe-RS racks.
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Redundant Operation: Seamlessly integrates with SCS redundancy configurations for fault-tolerant operation.
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Fast Sampling: Ideal for real-time safety-critical feedback with rapid input scanning.
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Channel Isolation: Each channel is isolated from the others to prevent signal interference or cascading faults.
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Easy Integration: Plug-in module with pre-terminated cables or terminal blocks for reduced wiring time.
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Environmental Durability: Operates under a wide temperature and humidity range.
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Long Lifecycle Support: Backed by Yokogawa’s industrial support policy for longevity and upgrade pathways.
Frequently Asked Questions (FAQ)
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What type of signals does the NFAI135 accept?
The NFAI135 is primarily designed for 4–20 mA DC analog signals, which are standard in industrial process instrumentation. -
Is the module suitable for safety-related applications?
Yes, it is SIL3 certified and specifically designed for use in Safety Instrumented Systems (SIS). -
Can the NFAI135 detect faults in field wiring?
Absolutely. It includes diagnostics such as open loop detection and out-of-range input detection. -
Does this module support redundant safety configurations?
Yes, it can be used in dual-redundant SCS architectures to ensure high availability. -
What type of isolation is implemented in the NFAI135?
It provides both channel-to-channel and channel-to-bus isolation for enhanced signal integrity. -
Can the module handle noisy industrial environments?
Yes, with high CMRR (Common Mode Rejection Ratio) and robust shielding, it is built for electrically noisy environments. -
How is the module powered?
It receives power via the ProSafe-RS SCS backplane, eliminating the need for external power wiring. -
How do I connect field wiring to the NFAI135?
Field wiring is typically connected via terminal blocks or pre-wired connectors depending on the rack setup. -
Can this module be hot-swapped?
While physical removal is possible, it is recommended to follow system shutdown procedures to maintain safety compliance. -
Which software is used to configure the NFAI135?
Configuration is done through ProSafe-RS Engineering Tools such as SENG and SCS Configurator within the Yokogawa environment.
Related Models (Same Series or Functional Category)
| Model | Function | Channels | Signal Type | System Compatibility |
|---|---|---|---|---|
| NFAI141 | Analog Input Module | 16 | 4–20 mA DC | ProSafe-RS |
| NFAT135 | Thermocouple Input Module | 16 | T/C (Type K, J, etc) | ProSafe-RS |
| NFDV151 | Digital Input Module | 16 | 24 VDC | ProSafe-RS |
| NFDV152 | Digital Output Module | 16 | 24 VDC | ProSafe-RS |
| NFAV161 | Analog Output Module | 8 | 4–20 mA DC | ProSafe-RS |
| NFCP100 | Control Processor Unit | N/A | CPU Module | ProSafe-RS |
Popular Yokogawa Models
| Model | Function | System | Key Feature |
|---|---|---|---|
| AAI543 | Analog Input Module | CENTUM CS3000 | Multi-signal support, high precision |
| ADV551 | Fast Analog Input Module | CENTUM VP | High-speed analog data acquisition |
| CP451 | Controller Processor Module | CENTUM VP | Advanced control with redundancy |
| YHC5150X | HART Communicator | Field Devices | Universal field device configuration |
| PW482 | Power Supply Module | ProSafe-RS | Dual-redundant power supply support |
| F3SP76-7S | High-Speed PLC CPU | FA-M3R | Designed for high-performance control |
