FUJI NQ2P20R-14 Programmable Logic Controller – NQ2 Series

FUJI NQ2P20R-14 Relay Output PLC – Compact Control Node for Discrete Automation Loops

The FUJI NQ2P20R-14 is a 20-point relay-output programmable logic controller belonging to FUJI Electric’s NQ2 Series. Within a discrete control loop, this unit functions as the deterministic decision engine: it samples 14 digital inputs at each scan cycle, executes the user ladder program against the current input image table, and drives 6 relay output contacts to actuate field devices — contactors, solenoid valves, pilot lamps, and motor starters — without requiring intermediate signal conditioning hardware. The relay contact architecture eliminates the need for external snubber networks on inductive loads up to the rated switching capacity, reducing panel wiring complexity and lowering mean-time-to-repair in field service scenarios.

The NQ2P20R-14 is positioned as a standalone, self-contained controller: CPU, I/O, and power supply are integrated into a single DIN-rail housing. This integration strategy reduces inter-module wiring, eliminates backplane connector failure modes associated with modular rack systems, and allows the unit to be deployed in space-constrained enclosures where a full rack-based PLC would be impractical. The compact form factor does not compromise scan performance — the NQ2 Series executes basic instructions at sub-millisecond cycle times, maintaining deterministic response margins required by most discrete machine control applications.

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Technical Parameters

Hardware Logical Analysis

The NQ2P20R-14’s input circuit employs optical isolation between the field wiring and the internal logic bus. Each digital input channel passes the field signal through an LED-photodetector pair rated for 2.5 kV isolation voltage, decoupling the controller’s CMOS logic from ground loops, common-mode transients, and inductive kickback generated by field devices sharing the same power distribution panel. The isolation barrier attenuates conducted EMI in the frequency range most damaging to CMOS gate arrays (1 MHz–100 MHz), which is the primary failure mechanism for PLCs installed adjacent to variable-frequency drives or large contactor banks.

The relay output stage uses electromechanical contacts rather than solid-state switching elements. This design choice has a direct consequence on load compatibility: relay contacts present near-zero on-state voltage drop (typically < 100 mV at rated current), eliminating the leakage current that solid-state outputs exhibit and which can cause false energization of sensitive solenoid valves or pilot relays with low holding-current thresholds. The mechanical contact also provides galvanic isolation between the output load circuit and the controller’s internal DC bus, a property that simplifies compliance with IEC 60204-1 machine safety wiring requirements.

The integrated power supply accepts a wide AC input range (100–240 V, ±10 %), incorporating an EMC filter stage at the AC inlet to suppress differential-mode and common-mode noise from the supply network. The internal DC/DC converter generates the isolated 5 VDC logic rail and the 24 VDC sensor supply rail independently, so voltage sag on the sensor supply (caused by a short-circuit on an input device) does not collapse the logic rail and cause a spurious CPU reset — a failure mode common in single-rail designs.

The NQ2 Series CPU executes a fixed-priority interrupt structure: high-speed counter interrupts and timed interrupts are serviced before the main scan cycle resumes, allowing time-critical tasks (e.g., encoder pulse counting, precise output timing) to operate with deterministic latency independent of the main program scan time. This architecture is functionally equivalent to a two-level scheduler, providing predictable response without requiring a real-time operating system.

System Integration Benefits

• Modbus RTU over RS-485: The built-in RS-485 port supports Modbus RTU master and slave modes, enabling direct integration with FUJI FRENIC inverters, third-party HMIs, and energy meters without gateway hardware — reducing network node count and latency.
• IEC 61131-3 Portability: Ladder Diagram and Function Block Diagram programs developed for the NQ2P20R-14 can be migrated to other IEC 61131-3 compliant platforms with minimal rework, protecting the engineering investment across machine generations.
• DIN-Rail Form Factor: The 35 mm DIN-rail mount is compatible with standard EN 60715 rail profiles used in IEC-standard control panels globally, eliminating custom mounting brackets in retrofit projects.
• Relay Output Load Flexibility: Relay contacts switch AC and DC loads interchangeably, allowing a single controller model to drive 24 VDC solenoids and 230 VAC contactors within the same panel without output module substitution.
• Integrated Diagnostics: The NQ2P20R-14 provides LED status indicators for each I/O point, power status, run/stop state, and communication activity, enabling field technicians to diagnose I/O faults without a programming terminal connected.
• Expansion Capability: The NQ2 platform supports expansion I/O modules (digital and analog), allowing the base unit to scale from 20 to over 100 I/O points without replacing the CPU, preserving the existing program and wiring.
• High-Speed Counter Input: Dedicated high-speed counter inputs (up to 10 kHz) support incremental encoder feedback and flow meter pulse counting directly at the CPU, eliminating the need for a separate counter module in motion-adjacent applications.
• Wide Temperature Operating Range: The 0–55 °C operating range covers the thermal envelope of most industrial panel enclosures without forced-air cooling, reducing fan maintenance requirements and associated particulate ingress risk.

Quality Assurance & Global Logistics

Every FUJI NQ2P20R-14 unit dispatched from our Xiamen, China facility is a genuine FUJI Electric original component, sourced through verified supply channels with full manufacturer traceability. Prior to shipment, each unit undergoes a multi-point inspection protocol: label authenticity verification against FUJI Electric’s current part numbering schema, physical housing integrity check, and communication port continuity test. Units are packed in anti-static foam-lined cartons with desiccant inserts to prevent moisture ingress during ocean or air freight transit.

Xiamen’s geographic position — a major southeastern China port city with direct air freight connections to Hong Kong, Singapore, Tokyo, Frankfurt, and Los Angeles — enables competitive transit times to most industrial procurement destinations. Air freight to Southeast Asia typically clears in 3–5 business days; to Europe and North America, 5–8 business days via express carriers (DHL, FedEx, UPS). Sea freight consolidation is available for volume orders where lead time permits. All shipments include commercial invoice, packing list, and certificate of origin documentation required for customs clearance in most jurisdictions. The 12-month warranty covers manufacturing defects and is supported by our technical team via email and WhatsApp.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
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