The FX2N-1HC is Mitsubishi Electric’s 1-channel high-speed counter special function module for the MELSEC FX2N compact PLC series, providing a dedicated high-speed pulse counting channel at up to 50 kHz with a built-in hardware comparison output — generating a hardware output signal the instant the counter value matches a preset comparison value, bypassing the FX2N CPU scan cycle to deliver sub-millisecond output response for precision cam switching, electronic limit switching, cut-to-length control, and register mark detection applications. As a dedicated hardware-speed counter with comparison output, the FX2N-1HC provides timing precision that the FX2N base unit’s software-based high-speed counter instructions cannot match for applications where output activation latency of 5–50 ms is unacceptable. Atlantech Drives holds stock of the FX2N-1HC. Contact us for fast worldwide delivery and competitive pricing.
What Is the FX2N-1HC?
The FX2N-1HC is a MELSEC FX2N series special function module providing one channel of high-speed pulse counting at up to 50 kHz with a hardware comparison output circuit that activates within 0.1 ms of the counter value reaching the preset comparison value. The module accepts AB quadrature, single-phase up/down, or CW/CCW pulse inputs from incremental encoders, proximity sensors, or pulse generators, with configurable counting modes selected via buffer memory parameter registers. The comparison value is loaded into the module’s comparison register via a TO instruction from the FX2N program, and the hardware output activates automatically when the counter reaches this value — independent of the FX2N CPU scan cycle, program execution status, or scan time overrun conditions. The FX2N-1HC also provides a latch input terminal that captures the current counter value on a rising edge external signal — useful for measuring the counter value at a precise external event (such as a part detection sensor) without software latency. The module communicates with the FX2N CPU via FROM/TO buffer memory instructions, with the current counter value, comparison status, and alarm outputs accessible in the buffer memory registers.
Key Technical Specifications
- Model: FX2N-1HC
- Counter Channels: 1
- Maximum Count Frequency: 50 kHz
- Counter Input Types: AB quadrature (×1, ×2, ×4), single-phase up/down, CW/CCW
- Counter Range: -2,147,483,648 to +2,147,483,647 (32-bit signed)
- Comparison Output: 1 hardware output (transistor, 24 VDC, activates within 0.1 ms of count match)
- Comparison Registers: 2 (upper and lower comparison values for window output)
- Latch Input: 1 (captures counter value on rising edge)
- Extension Bus Occupation: 8 I/O points
- External Power Supply: 24 VDC ±10%, 100 mA (required)
- Operating Temperature: 0°C to 55°C
- Compatible FX2N base units: All FX2N models
- Weight: Approx. 0.15 kg
Compatibility & System Integration
The FX2N-1HC is compatible with all FX2N base units and integrates into the FX2N extension bus alongside I/O extension modules and other special function modules. The module’s hardware comparison output terminal connects directly to the field actuator requiring immediate activation — the 0.1 ms response ensures the output activates at the correct mechanical position regardless of FX2N CPU scan time variability. The FX2N-1HC is commonly paired with the FX2N-1PG-E or FX2N-10PG positioning modules in the same FX2N extension bus: the positioning module drives the servo axis while the FX2N-1HC monitors a secondary encoder on the mechanical load for position verification or provides the cam output for a secondary process action at a precise mechanical position. In cut-to-length systems, the FX2N-1HC counts encoder pulses from a measurement wheel and activates the cut actuator output at the programmed length position with 0.1 ms activation latency — the comparison value is updated by the FX2N program after each cut to set the next cut position. For electronic cam applications, the FX2N-1HC’s upper and lower comparison values define a window — the comparison output activates when the counter is between the upper and lower threshold values — enabling the output to remain ON for a configurable angular range of a rotary machine cycle. The FX2N-1HC’s latch input function is used in registration mark detection systems: when the web’s printed registration mark passes under a photoelectric sensor connected to the latch input, the current counter value is captured instantly and read by the FX2N program via a FROM instruction to calculate the registration error for phase correction.
Troubleshooting Guide
If the FX2N-1HC comparison output fails to activate at the expected counter value, verify first that the comparison value has been correctly written to the module’s comparison register via a TO instruction — use GX Works2’s special function module buffer memory monitor to read the comparison register and confirm the value matches the intended threshold. A common error is writing the comparison value in a non-persistent ladder rung that only executes under a specific condition, causing the comparison value to revert to zero (default) when the condition is inactive. Write the comparison value from a latched data register (using SET/RST) rather than a contact-triggered rung to ensure the comparison register always contains a valid comparison value. For the comparison output activating at incorrect positions (consistent offset), verify the encoder resolution and counting mode are correctly configured — an AB quadrature encoder configured in ×4 multiplication mode provides 4 counts per encoder line rather than 1 count, so a 1,000 line encoder provides 4,000 counts per revolution in ×4 mode but only 1,000 in ×1 mode. Verify the FX2N-1HC counting mode register (BFM#1) against the intended configuration. For erratic counter values or false triggering of the comparison output, inspect the encoder cable routing — the FX2N-1HC’s 50 kHz input is susceptible to induced noise from adjacent VFD output cables at high count rates. Maintain at least 200 mm physical separation between encoder cables and motor power cables, and verify the encoder cable shield is connected to earth at the FX2N-1HC terminal end only.
Frequently Asked Questions
Q: Can the FX2N-1HC’s comparison output be configured to activate only when the counter is within a range (window detection) rather than at a single threshold?
A: Yes. The FX2N-1HC provides two comparison registers — an upper comparison value and a lower comparison value — that define a counting window. The hardware comparison output activates when the counter value is within the window (greater than or equal to the lower value AND less than or equal to the upper value) and deactivates when the counter is outside the window. Configure the window boundaries via TO writes to BFM#2 (lower comparison) and BFM#3 (upper comparison). This window detection mode is used for cam applications where the output must remain active during a specific angular range of machine rotation.
Q: What is the maximum encoder frequency the FX2N-1HC can count in AB quadrature ×4 mode?
A: The FX2N-1HC accepts input signal frequencies up to 50 kHz. In AB quadrature ×4 mode, the physical encoder frequency is limited to 50 kHz ÷ 4 edges per cycle = 12.5 kHz (12,500 RPM for a 1-line encoder, or 1,250 RPM for a 1,000-line encoder). For higher encoder physical frequencies, use the ×1 or ×2 counting mode which allows higher physical encoder frequency at reduced resolution. The 50 kHz limit applies to the input signal frequency seen by the counter circuit — in ×4 mode, each encoder line generates 4 counted edges, so the maximum physical encoder frequency is 50 kHz ÷ 4 = 12.5 kHz.
Q: Can the FX2N-1HC replace the FX2N base unit’s C235 high-speed counter in a cut-to-length application?
A: The FX2N-1HC provides a dedicated hardware comparison output that responds within 0.1 ms of the count threshold, while the FX2N base unit’s C235 high-speed counter relies on the PLC program scan to detect the comparison match and activate an output — introducing a variable 5–50 ms response delay. For cut-to-length applications where cutting accuracy depends on activating the cut solenoid at a precise encoder count, the FX2N-1HC’s 0.1 ms hardware response provides substantially better cut length accuracy than C235 software comparison, particularly at high material speeds where 5–50 ms of latency corresponds to significant cut length error.
Do you need more references from this brand? Explore our full catalog of Mitsubishi here: https://atlantechdrives.com/manufacturers/mitsubishi/
