Contactor,circuit breaker,sensor,Encoder,PLC,Converter
FX2NC ultra-compact micro PLC (DC24V powered, transistor output, End-of-Life / discontinued; only second-hand or stock spare parts available)
Model Code Explanation
FX2NC: FX2N ultra-compact series (C = Compact)
96: Total I/O points 96 points
M: Main Unit (integrated CPU)
T: Transistor output (Sink type; high-speed pulse output for servo/stepper drive)
- Core I/O Specifications
Input: 48 points X0~X57, DC24V sink input
Output: 48 points Y0~Y57, DC24V sink transistor output
Total I/O: 96 points; maximum expanded system I/O ≤256 points, input or output single direction ≤184 points
Power Supply: DC24V, voltage range DC24V -15% ~ +20%, peak-to-peak ripple ≤5%
Mechanical: Ultra-thin pluggable terminal structure, DIN rail mounting; weight approx. 0.45 kg
- Program & Memory
Built-in RAM: 8K steps (lithium battery backup)
Optional memory cards: FX2NC-EEPROM4C / 16C (with RTC real-time clock), FX2NC-EEPROM16 (no RTC); max program capacity 16,000 steps
Programming Languages: Ladder Diagram, SFC Sequential Function Chart
Basic instruction execution speed: 0.08 μs per instruction
Onboard real-time clock: Requires FX2NC-RTC or EEPROM card with RTC
- Expansion & Communication
- Expansion: Direct connection to FX0N / FX2NC expansion blocks. To use standard FX2N modules, FX2NC-CNV-IF conversion adapter is mandatory.
- Special modules: Supports FX2N-series analog I/O, positioning, CC-Link modules, limited by 5V bus current capacity.
- Communication: RS232 / RS485 via external ADP adapters (FX2NC-232ADP / 485ADP).
- Host 5V power budget: Supplies power to expansion modules; must not exceed the host 5V current rating. Current load calculation required for expansion selection.
- Suffix Variants
FX2NC-96MT-D: Base DC24V model
FX2NC-96MT-DS: DC24V, overseas specification
FX2NC-96MT-DSS: DC24V, dual sink/source output, UL certified
- Discontinuation & Replacement Options (Key)
✅ Official recommended drop-in replacement: FX3UC-96MT/D, highly compatible hardware and program; GX Works2 supports direct FX2NC program conversion.
✅ Next-generation upgrade option: FX5UC-96MT/D (iQ-F), higher performance; wiring and program migration evaluation required.
Note: Not pin-for-pin interchangeable. Terminal layout, power logic and battery model differ. Wiring, expansion bus and battery backup must be rechecked for retrofit projects.
- Typical Applications
Space-constrained compact automation, packaging machinery, conveyor lines, stepper / servo positioning control. Transistor outputs are designed for pulse servo drive; cannot directly drive high-power AC contactors.
- Maintenance & Common Faults
- Battery Model: FX2NC-32BL lithium battery for program/register retention. Low-battery alarm via special registers; service life ~5 years, now end-of-life and spare parts scarce.
- Common Faults
BATT LED ON: D8005 monitors battery voltage; risk of program/data loss.
ERR LED / Power fault: Excessive DC24V fluctuation, high ripple, or overload on expansion 5V bus.
No input response: Oxidation on plug-in terminals (very common failure point for FX2NC).
No pulse from Y outputs: Output common terminal wiring, load polarity or pulse instruction parameter errors.
- Programming Software: GX Developer / GX Works2; programming cable FX-USB-AW or RS422 download cable required.
- Second-Hand Unit Inspection Checklist (Spare Procurement)
- No burn marks on housing; plug terminal sockets intact with no pin corrosion or cracking.
- Power on and check POWER / ERR LEDs; read battery voltage from D8005.
- Verify EEPROM memory card read/write operation.
- Force all X/Y I/O points one-by-one to confirm switching function.
- Back up original program and verify firmware version.
- Program Migration Checklist (FX2NC → FX3UC)
- Upload FX2NC program in GX Works2 and save project.
- Change PLC model within project to FX3UC-96MT/D, run program conversion, resolve incompatible legacy instruction errors.
- Verify special M/D registers, high-speed counters and pulse output addresses.
- Redesign expansion layout; remove FX2NC-CNV-IF (FX3UC directly supports FX3U modules).
- Redraw terminal wiring diagrams: I/O addresses remain the same but physical terminal positions differ.
- Re-evaluate battery replacement scheme and retentive register parameters.
- No-lod power-on test, followed by loaded commissioning.
- Same Series Model Comparison
FX2NC-16MT / 32MT / 64MT / 96MT, identical architecture with increasing I/O count.
FX2NC (FX2NC-96MT) Fault Code & Special Alarm Register List
Reading method: Monitor D8060~D8068 online in GX Developer/GX Works2; M80xx = alarm flags. D8004 stores the register number of the highest priority active error.
Hardware LED reference: BATT LED = battery alarm; ERROR flashing = program / parameter fault; ERROR steady ON = fatal CPU hardware fault
- Core Alarm M Relays (M8060~M8068)
| Element | Description | Behavior | Remarks |
| M8004 | Global Error Flag | ON = any fault present | Activated when any of M8060~M8068 is ON |
| M8005 | Low Battery Voltage | BATT LED ON | Battery voltage read via D8005; triggers below threshold |
| M8006 | Latch Low Battery | Latched ON | Retains low-battery history, not cleared by power cycle |
| M8060 | I/O Configuration Error | RUN enabled | Program-defined I/O / expansion modules mismatch physical hardware; D8060 = starting I/O address of fault |
| M8061 | PLC Hardware Error | ERROR steady ON, PLC STOP | CPU, RAM or I/O bus failure; D8061 holds hardware error code |
| M8062 | Programmer / Peripheral Comm Error | RUN enabled | Faulty programming cable or HOST communication; D8062 = comm error code |
| M8063 | Parallel Link / RS485 Comm Error | RUN enabled | Multi-drop parallel link or 485ADP fault; D8063 = comm error code |
| M8064 | Parameter Error | ERROR flashing, STOP | Invalid PLC parameters (I/O size, memory, station number); D8064 error code |
| M8065 | Syntax Error | ERROR flashing, STOP | Program syntax fault; reported during download; D8065 error code |
| M8066 | Circuit Error | ERROR flashing, STOP | Ladder logic error (e.g. coil directly connected to main bus); D8066 error code |
| M8067 | Operation Error | RUN continues | Instruction runtime fault (division by zero, register overflow, invalid address); D8067 error code |
| M8068 | Latched Operation Error | RUN continues | Latch retains runtime fault, persists through power cycle, manual reset required; D8068 latched error code |
| M8069 | I/O Bus Check Bit | Manual ON trigger | Starts I/O bus diagnostic test; bus faults write 6103/6104 to D8061 |
- D Register Fault Codes (D8061/D8062/D8063)
D8061 (Hardware Error Codes)
| Code | Fault Description | Troubleshooting |
| 0 | No hardware fault | – |
| 6101 | RAM abnormality | Memory damage; replace PLC |
| 6102 | CPU arithmetic circuit failure | Main unit hardware damage |
| 6103 | I/O Bus Error | Loose/corroded FX2NC expansion plug, FX2NC-CNV-IF adapter or expansion cable |
| 6104 | Missing 24V supply to expansion unit | DC24V power lost for expansion modules; D8009 logs fault unit starting I/O address |
D8062 (Programming Port / Peripheral Communication Errors)
| Code | Fault Description |
| 0 | Normal |
| 6201 | Parity / Overrun / Framing error (serial noise, baud rate mismatch) |
| 6202 | Character error |
| 6203 | Checksum error |
| 6204 | Data format error |
| 6205 | Instruction error |
D8063 (Parallel Link / 485ADP Communication Errors)
| Code | Fault Description |
| 0 | Normal |
| 6301 | Parity / Overrun / Framing error |
| 6302 | Character error |
| 6303 | Checksum error |
| 6304 | Data format error |
| 6305 | Instruction error |
| 6306 | WDT Timeout (long communication blockage) |
- D8000~D8009 System Diagnostic Registers (Auxiliary)
D8000: Watchdog timer setting (default 100 ms)
D8001: PLC firmware version + memory capacity
D8002: Memory type (00H=RAM, 02H=EEPROM protection OFF, 0AH=EEPROM protection ON)
D8003: Backup memory error flag
D8004: Register number of highest priority active error (e.g. 8061 = hardware fault)
D8005: Battery voltage, unit = 0.01V (example: 300 = 3.0V; alarm approx. below 2.7V)
D8006: Low battery detection threshold
D8007: Momentary power failure counter
D8008: Momentary power loss detection time
D8009: Starting I/O address of expansion unit with 24V loss (valid when M8009 = ON)
- Special Module Faults (Analog / Positioning / CC-Link)
FX2NC expansion special modules (FX2NC-4AD, 4DA, 1PG, 32CCL, etc.) do not use D806x. Read BFM29 for module error codes via FROM instruction.
BFM29 b0=1: Module has any fault
b1: Offset/gain EEPROM abnormality
b2: Module 24V power fault
b3: Module hardware fault
b4: Misuse of FROM/TO instructions
Remaining bits vary by module type (positioning, CC-Link etc.)
- Fast Troubleshooting Flow (FX2NC-96MT)
- Check LEDs: BATT ON → battery fault; ERROR flashing → program/parameter; ERROR steady ON → CPU hardware fault
- Monitor D8004 online to identify active M80xx fault source
- Read corresponding D806x to get detailed error code
- Operation faults M8067/M8068: Locate faulty instruction; M8068 requires manual reset
- I/O bus error 6103: Inspect FX2NC expansion plugs and FX2NC-CNV-IF pins for oxidation (high frequency FX2NC failure)
- Communication errors 62xx/63xx: Verify baud rate, cable shielding and terminating resistors
- Differences vs FX3UC (Migration Reference)
FX3UC retains the M8060~M8068 system with extra alarm registers; base 61xx/62xx/63xx fault codes have identical definitions. Diagnostic logic can be reused after migration.
Mitsubishi FX2NC Full Series Model List (MELSEC-F FX2NC Ultra-Compact PLC, all EOL discontinued)
Suffix Definition
D: DC24V supply; DS: overseas spec; DSS: dual sink/source output + UL certification
T: pluggable connector; R = relay output; T = transistor output
All CPUs are DC24V powered. No AC powered FX2NC main units.
- CPU Main Units
| Model | Total I/O | Input X | Output Y | Output Type |
| FX2NC-16MT | 16 | 8 | 8 | Transistor |
| FX2NC-16MT-D | 16 | 8 | 8 | Transistor |
| FX2NC-16MT-DSS | 16 | 8 | 8 | Transistor (Dual polarity UL) |
| FX2NC-16MR-T-DS | 16 | 8 | 8 | Relay (European screw terminal block) |
| FX2NC-32MT | 32 | 16 | 16 | Transistor |
| FX2NC-32MT-D | 32 | 16 | 16 | Transistor |
| FX2NC-32MT-DSS | 32 | 16 | 16 | Transistor (Dual polarity UL) |
| FX2NC-64MT | 64 | 32 | 32 | Transistor |
| FX2NC-64MT-D | 64 | 32 | 32 | Transistor |
| FX2NC-64MT-DSS | 64 | 32 | 32 | Transistor (Dual polarity UL) |
| FX2NC-96MT | 96 | 48 | 48 | Transistor (target unit) |
| FX2NC-96MT-D | 96 | 48 | 48 | Transistor |
| FX2NC-96MT-DSS | 96 | 48 | 48 | Transistor (Dual polarity UL) |
- FX2NC Dedicated I/O Expansion Modules (Direct plug to FX2NC host, no CNV-IF)
Input Expansion (EX)
FX2NC-16EX / FX2NC-16EX-DS: 16-point DC24V input (plug connector)
FX2NC-16EX-T / FX2NC-16EX-T-DS: 16-point DC24V input (screw terminal block)
FX2NC-32EX / FX2NC-32EX-DS: 32-point DC24V input
Output Expansion (EYT Transistor / EYR Relay)
FX2NC-16EYT / FX2NC-16EYT-DSS: 16-point transistor output
FX2NC-16EYR-T-DS: 16-point relay output (screw terminal)
FX2NC-32EYT / FX2NC-32EYT-DSS: 32-point transistor output
FX2NC-64ET: 64-point mixed I/O (32-in +32-out), transistor output
Note: FX0N and standard FX2N expansion modules cannot plug directly into FX2NC. FX2NC-CNV-IF conversion adapter required.
- Memory, Clock & Option Boards
FX2NC-EEPROM-4C: 4K-step EEPROM card with RTC real-time clock
FX2NC-EEPROM-16C: 16K-step EEPROM card with RTC (common variant)
FX2NC-EEPROM-16: 16K-step EEPROM, no real-time clock
FX2NC-RTC: Real-time clock board (memory not included, adds RTC only)
FX2NC-ROM-CE1: Extended ROM board for inverter communication EXTR instruction
FX2NC-32BL: Backup lithium battery for program / register retention
FX2NC-10BPCB1 / FX2NC-100BPCB: Terminal adapter baseplate
- Communication Adapters (side-mounted to CPU)
FX2NC-232ADP: RS232 communication adapter
FX2NC-485ADP: RS485 communication adapter (parallel link, Modbus)
- Conversion Adapter
FX2NC-CNV-IF: Interface converter between FX2NC and FX0N/FX2N standard expansion modules (high-demand spare part)
- Compatible General Special Modules (Requires FX2NC-CNV-IF)
FX2N series special modules, usable with FX2NC only via CNV-IF adapter
FX2N-4AD: 4-ch analog input
FX2N-4DA: 4-ch analog output
FX2N-4AD-PT: 4-ch PT100 RTD
FX2N-4AD-TC: 4-ch thermocouple
FX2N-1HC: High-speed counter module
FX2N-1PG-E: Single-axis pulse positioning module
FX2N-1RM-E: Programmable cam module
FX2N-32CCL: CC-Link slave module
- System Key Points
- Max total I/O for FX2NC system: 256 points (host + FX2NC expansion + FX2N expansion combined)
- All main CPUs are transistor output; FX2NC-16MR-T-DS is the only relay-output main unit
- Two expansion families: FX2NC slim expansion direct plug; FX2N standard modules require CNV-IF adapter
- All series discontinued; only second-hand, pulled or leftover stock available. FX2NC-32BL backup batteries also becoming scarce.
