Key Technical Specifications
- Manufacturer: FUJI ELECTRIC CO., LTD.
- Product Type: Standard Baseboard
- Slot Capacity: 8 Slots (Excluding Power Supply)
- Internal Current Consumption: 50 mA or less
- Bus Architecture: SX Bus (8 Slots) + Processor Bus (3 Slots)
- Dimensions (W1 x W2): 308 mm x 290 mm
- Weight: Approximately 540 g
- Country of Origin: Japan
Product Introduction
Control cabinets get cramped fast when you’re trying to squeeze a PLC, power supply, and a dozen I/O modules into a tight space. The FUJI NP1BS-08 baseboard was built exactly for this headache. It acts as the central nervous system for FUJI’s compact SPB controllers, providing the physical slots and internal bus routing for up to 8 expansion modules without eating up excessive panel real estate.Engineers stick with this specific baseboard because it handles the heavy lifting of internal power distribution while drawing a mere 50mA for its own internal logic. That leaves your 24VDC power supply to actually do its job powering the field I/O. I’ve wired up dozens of these in tight automation panels; the 308mm width is predictable, and the SX bus layout keeps high-speed I/O refresh rates stable. Just make sure you don’t confuse the W1 and W2 dimensions when cutting your DIN rail or drilling panel holes.
Quality SOP & Tech Pitfalls
We don’t just ship old PLC parts and hope they work. Every NP1BS-08 that leaves our bench goes through a strict validation process. First, we do a visual and counterfeit check under magnification to ensure the FUJI branding and PCB traces are genuine. Next, it goes onto our live SPB test rack where we verify that all 8 SX bus slots can successfully handshake with CPU and I/O modules. We pull out a Fluke 115 to check insulation resistance and ensure there are no internal shorts on the 24VDC distribution rails. Finally, we log the hardware revision and ship it in anti-static packaging.Here is the brutal truth about swapping these baseboards: Never assume the power supply is included. The NP1BS-08 baseboard does not contain the power supply. I once watched a junior tech spend four hours troubleshooting a “dead” PLC, only to realize he had wired his 24VDC directly to the baseboard’s logic pins instead of installing the dedicated NP1PS power module. Also, if you are replacing a failed board, photograph the existing wiring and DIP switch settings before touching anything. SX bus termination and slot addressing can be unforgiving if you guess.
Installation & Configuration Guide
- Pre-Installation Safety: ⚠️ LOCKOUT/TAGOUT. Disconnect all incoming AC and 24VDC power. Wait at least 5 minutes for internal capacitors to discharge. Take high-resolution photos of all existing wiring, especially the 24VDC input and ground connections.
- Removal: Label every single wire before disconnecting. Release the DIN rail mounting clips carefully—plastic gets brittle with age and heat. Do not pry the board out by the connectors.
- Installation: COPY ALL DIP SWITCH AND JUMPER SETTINGS EXACTLY. 90% of “new board won’t boot” calls are caused by mismatched slot addressing or SX bus configuration. Slide the NP1BS-08 onto the DIN rail, ensuring the top and bottom hooks catch securely. Reconnect wiring exactly as photographed.
- Power-On & Testing: Apply 24VDC power and monitor the PSU indicator LEDs. Verify that the CPU module boots and recognizes all 8 slots in the programming software. Run a quick I/O force test on each slot to confirm backplane communication is solid.
Compatible Replacement Models
| Model | Compatibility Tier | Notes |
|---|---|---|
| NP1BS-08 | ✅ Drop-in Replacement | Exact match. 8-slot standard baseboard. |
| NP1BS-08S | ✅ Drop-in Replacement | Functionally identical; “S” suffix typically denotes a minor manufacturing revision or regional spec. |
| NP1BS-06 | ❌ Hardware Mod Required | Only 5 slots. Requires removing I/O modules or changing system architecture. Not recommended. |
Frequently Asked Questions (FAQ)
Does this baseboard include the power supply?
No. The NP1BS-08 is strictly a backplane and slot holder. You must purchase the corresponding power supply module (like the NP1PS series) separately. The baseboard only draws 50mA for its own internal bus logic.Can I hot-swap I/O modules on this baseboard while the CPU is running?
Absolutely not. The SPB series SX bus is not designed for hot-swapping. Pulling a module while powered will likely cause a bus fault, drop your CPU into a fault state, and potentially fry the backplane traces. Always power down first.I’m replacing an old NP1BS-08. Will my existing CPU and I/O modules plug right in?
Yes, the physical footprint and SX bus pinout for the standard NP1BS-08 have remained consistent. However, you must verify that your CPU’s firmware supports the hardware revision of the replacement baseboard. Check the FUJI SPB hardware manual for your specific CPU model.How much panel space do I need to allocate for this?
You need to account for a width of 308mm (W1 dimension). Make sure you leave at least 20mm of clearance on both sides for airflow and wire bending radius. Cramming it flush against another DIN rail component is a recipe for overheating.Is this board still manufactured by FUJI?
The SPB series is a legacy platform. While FUJI still supports it, finding brand-new, factory-sealed units is getting harder. What we have in stock are verified new surplus units imported directly from Japan. If you need a long-term migration path, we should talk about upgrading to the newer MICREX-SX series.What happens if I wire 24VDC to the wrong terminal?
The baseboard has limited reverse-polarity protection. If you wire it backward, you will likely blow the internal fuse on the baseboard or destroy the CPU module’s power input stage. Triple-check your multimeter reading before flipping the breaker.
