Product Core Brief
- Model: NFAI841-S00
- Brand: YOKOGAWA
- Series: STARDOM FCN-RTU Analog I/O Module
- Core Function: Provides 8 analog 4–20 mA DC inputs and 8 analog 4–20 mA DC outputs for STARDOM FCN-RTU controllers.
- Product Type: Analog Input/Output Module
- Key Specs: 8 × 4–20 mA DC input | 8 × 4–20 mA DC output | Non-isolated I/O
- Condition: New Surplus / OEM Genuine
- Note: Suffix “-S00” is not fully verified in available references; confirmed variants include NFAI841, NFAI841-SE0, and NFAI841-SE1.
Key Technical Specifications
- System compatibility: STARDOM FCN-RTU autonomous controller
- Module type: Analog input/output
- Input channels: 8 × 4–20 mA DC
- Output channels: 8 × 4–20 mA DC
- Isolation: Non-isolated
- Mounting: FCN-RTU I/O slot
- Typical application: Process monitoring, RTU expansion, field signal conditioning
- Status: Discontinued / legacy module
- Verification status: Suffix “-S00” requires nameplate confirmation
Product Introduction
This module expands STARDOM FCN-RTU systems with eight 4–20 mA DC inputs and eight 4–20 mA DC outputs. It is used where remote process signals must be acquired and driven from a single analog I/O card.
Because the module is non-isolated, loop grounding and power routing must be checked before commissioning. It is a practical replacement option for legacy FCN-RTU racks, but the exact suffix should match the original engineering documentation.
QA & Testing SOP
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- Verify the nameplate reads and check for damage, rework marks, or mismatched labels.
- Inspect the backplane connector for bent pins, corrosion, or loose housing before insertion.
- Install into an FCN-RTU rack and confirm the controller detects the module without fault codes.
- Inject 4 mA and 20 mA on sample input channels and verify scaled readings match the engineering unit range.
- Command 4 mA and 20 mA outputs and measure loop current with a Fluke multimeter; confirm accuracy and stability.
- Pack in anti-static shielding with foam support for shipment.
Installation Pitfalls & Guide
❗ Non-isolated I/O: All channels share a common reference. Mixing grounded and ungrounded loops can create ground offsets.
❗ Suffix mismatch: NFAI841-S00 is not automatically interchangeable with NFAI841-SE0, NFAI841-SE1, or HART-enabled variants.
❗ Hot insertion risk: Do not insert or remove the module while the rack is powered unless the OEM manual explicitly allows it.
❗ Loop power routing: Confirm whether the field devices are loop-powered or externally powered before wiring.
Replacement steps
- Document the existing module code, slot position, and loop wiring.
- Power down the FCN-RTU rack if hot-swap is not approved.
- Remove the old module and inspect the backplane connector.
- Install the replacement, restore power, and verify I/O channel status.
Technical FAQ
Is still available?
It is a discontinued STARDOM FCN-RTU module. Availability depends on surplus inventory and should be confirmed before ordering.
Can I replaceith ?
Not automatically. The “-S00” suffix is not fully verified, and SE variants may differ in isolation, HART support, or environmental rating. Match the original part number exactly.
Does this module support HART?
No. The NFAI841 base family is a standard 4–20 mA analog module. HART capability appears on other STARDOM configurations, not on this non-isolated analog I/O card.
What warranty applies?
Surplus modules typically carry a limited functional warranty. Exact terms depend on stock condition and should be confirmed at quotation.
Can I use it in a CENTUM VP rack?
No. This module belongs to the STARDOM FCN-RTU platform. CENTUM VP analog modules such as AAI841 use a different hardware family and are not direct replacements.
