The QX80 is Mitsubishi Electric’s 32-point 24 VDC sink digital input module for the MELSEC-Q programmable controller series — providing 32 optically isolated 24 VDC sink (NPN-compatible) input points in a single-slot module for the Q-series base unit, the standard high-density digital input module for MELSEC-Q systems requiring comprehensive field signal input capability in a compact single module footprint. In stock at Atlantech Drives. Request your quote within 24-48 hours with worldwide shipping and 12-month warranty.
What Is the QX80?
The QX80 is a MELSEC-Q series digital input module providing 32 individually optically isolated 24 VDC sink input points — the highest input point density available in a single MELSEC-Q standard I/O module slot, making the QX80 the preferred input module for MELSEC-Q systems with large numbers of field signals to monitor. The module installs in any I/O slot in a Q-series main or extension base unit, and the 32 input addresses are automatically assigned by the MELSEC-Q CPU’s I/O assignment based on the module’s physical slot position — no software configuration is required for basic I/O operation beyond the standard GX Works2 I/O assignment verification. Each of the QX80’s 32 input points accepts 24 VDC signals from NPN-output (sink current) proximity sensors, photoelectric sensors, limit switches, push buttons, and other 24 VDC binary signal sources. The input circuits are individually optically isolated from the MELSEC-Q internal bus, providing galvanic separation between field sensor circuits and PLC logic for electrical noise immunity and safety. The QX80’s high input density (32 points per module versus 16 points for the QX40) effectively doubles the input capacity per base unit slot, enabling larger MELSEC-Q systems to be built in fewer base unit slots — important when base unit slot count is the primary system expansion constraint.
Key Technical Specifications
- Model: QX80
- Input Points: 32
- Input Type: 24 VDC sink (NPN-compatible)
- Input Voltage Range: 20.4–28.8 VDC (signal ON), ≤6 VDC (signal OFF)
- Input Current: 4 mA typical at 24 VDC
- Response Time: 10 ms standard (adjustable 1–70 ms via parameter)
- Isolation: Optical, per input point
- Common Configuration: 32 points per common (shared common terminal)
- Connector: 40-pin connector (requires Q series I/O terminal block or connector cable)
- Power Consumption: 5 VDC internal bus, approx. 0.09 A
- Operating Temperature: 0°C to 55°C
- Dimensions (W × H × D): 27.4 mm × 98 mm × 89.3 mm
- Weight: Approx. 0.10 kg
Compatibility & System Integration
The QX80 is compatible with all MELSEC-Q main base units (Q3□B, Q5□B, Q6□B, Q3DB) and extension base units (Q6□B, Q6DB) — installation in any I/O module slot provides automatic 32-point input address assignment by the Q-series CPU’s I/O assignment scan. The QX80 uses a 40-pin connector (not screw terminal block) — field wiring requires either the Mitsubishi A6CON1 (solder-type) or A6CON2 (crimp-type) 40-pin connector assembly for direct field wire termination, or the QA1S65B terminal block adapter with MR-50-LM connecting cable for screw terminal field wiring. When planning the base unit layout, note that the QX80’s 40-pin connector with field wiring requires more front-of-panel depth than screw terminal I/O modules — allow adequate panel depth for the connector and cable bend radius in front of the QX80. In multi-CPU MELSEC-Q systems (Q02UCPU + Q172DSCPU motion CPU in the same base unit), the QX80 input data is accessible to both CPUs via the multi-CPU shared I/O device mapping, enabling sequence CPU ladder programs and motion CPU motion programs to read QX80 input states. For high-speed input applications requiring faster than 10 ms response, the QX80’s programmable response time (adjustable from 1 ms to 70 ms via the I/O module parameter settings in GX Works2) can be reduced to 1 ms for individual input points — reducing the response time increases the module’s susceptibility to input noise, so apply minimum response time only to inputs requiring rapid response and verify adequate signal filtering at the sensor level.
Installation Advice
The QX80’s 40-pin connector field wiring requires careful planning — 32 input signals plus common (0 VDC) in a 40-pin connector body demands organised wiring with consistent conductor colour coding and labelling. Use 0.3–0.75 mm² conductors for the QX80 input wiring (smaller than the 1.5–2.5 mm² typical for relay output wiring), and group conductors from the same field zone together within the connector for easier fault diagnosis. For the QX80’s common (COM) terminal — which is the 0 VDC return for all 32 sink input circuits simultaneously — use a conductor of at least 1.0 mm² cross-section to handle the combined return current from multiple simultaneous activated inputs without excessive voltage drop across the common wire. Excessive common wire resistance causes all 32 input OFF thresholds to shift upward simultaneously when multiple inputs are activated, potentially causing marginal input signals to be misread as OFF when many other inputs are simultaneously ON. In MELSEC-Q systems where multiple QX80 modules are installed in the same base unit, assign each QX80’s common terminal to a dedicated 0 VDC return run from the panel’s 24 VDC power supply — sharing a single common return wire between multiple QX80 modules multiplies the current on the shared common and amplifies the voltage drop issue described above. Label the QX80 module’s slot position and its I/O address range in GX Works2’s I/O assignment on the panel door label — in large MELSEC-Q systems with multiple QX80 modules, the slot-to-address mapping must be documented for rapid fault diagnosis without requiring GX Works2 online connection.
Frequently Asked Questions
Q: Can the QX80 accept PNP (source) input signals, or is it limited to NPN (sink) sensors?
A: The QX80 uses sink input circuits — the input activates when the input terminal is pulled toward 0 VDC by the sensor output. PNP-output (source) sensors that source 24 VDC to the input terminal are not directly compatible with the QX80’s sink input. For PNP sensor compatibility, the QX82 (32-point source/sink selectable input module) or the QX41-S2 (source input) should be specified instead of the QX80. Inline NPN-to-PNP conversion devices can also adapt PNP sensors to the QX80’s sink input, but this adds cost and panel space per input channel.
Q: What is the difference between the QX80 and the QX40 in terms of application suitability?
A: The QX80 provides 32 input points per module versus 16 for the QX40, at the same module width — effectively doubling input density per base unit slot. The QX80 uses a 40-pin connector (not screw terminals), requiring a connector assembly or terminal block adapter for field wiring, while the QX40 uses a more convenient 18-point screw terminal block for direct field wiring. Specify the QX80 when maximising input density per base unit slot is the priority and the 40-pin connector wiring method is acceptable; specify the QX40 when direct screw terminal field wiring convenience is more important and base unit slots are not the primary constraint.
Q: Does the QX80 support interrupt input function for sub-scan response to critical input events?
A: The QX80 standard module does not support hardware interrupt input — interrupt input in MELSEC-Q systems requires the QX40-S1 or QX28-S1 interrupt input modules with dedicated interrupt signal processing. For sub-scan response to critical inputs (emergency stop, limit overtravel, web break detection), use the QX40-S1 for the critical signals requiring interrupt response, and use the QX80 for the remaining non-critical status inputs in the same base unit.
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