The QY40P is Mitsubishi Electric’s 32-point transistor source (PNP) digital output module for the MELSEC-Q programmable controller series — providing 32 optically isolated 24 VDC source (PNP-compatible) transistor output points in a single-slot module for the Q-series base unit, the high-density transistor source output module for MELSEC-Q systems requiring solid-state output switching of 24 VDC loads with PNP sourcing interface and unlimited electrical switching life. Atlantech Drives holds stock of the QY40P. Contact us for fast worldwide delivery and competitive pricing.
What Is the QY40P?
The QY40P is a MELSEC-Q series digital output module providing 32 individually optically isolated 24 VDC source (PNP) transistor output points — each output point sourcing 24 VDC to the load when the output is ON, compatible with NPN-input load devices (solenoid valves with NPN input indicators, relay coil inputs, step motor driver enable inputs). The «P» suffix in the model designation identifies the source (PNP) output polarity — as distinct from the QY80 which provides 32-point sink (NPN) transistor outputs that pull the output terminal to 0 VDC when ON. Source outputs (QY40P) are standard in European and international machine control specifications where the 24 VDC positive rail is switched to the load, while sink outputs are more common in Japanese and some Asian machine specifications — verify the output polarity requirement against the field device’s input specifications before selecting between QY40P (source) and QY80 (sink). Each QY40P output point is rated at 0.1 A continuous per point (32 × 0.1 A = 3.2 A total simultaneously), appropriate for 24 VDC solenoid valve coils (typically 0.1–0.3 A), relay coil inputs (typically 0.01–0.05 A), and indicator lamps (typically 0.02–0.05 A). The module uses a 40-pin connector for field wiring — the same physical connector format as the QX80 32-point input module, enabling consistent field wiring approach across high-density I/O modules in the same MELSEC-Q panel.
Key Technical Specifications
- Model: QY40P
- Output Points: 32
- Output Type: Transistor source (PNP) — output sources 24 VDC to load when ON
- Output Voltage: 20.4–28.8 VDC (external supply)
- Output Current: 0.1 A per point maximum
- Total Simultaneous Output Current: 3.2 A (all 32 points ON simultaneously)
- Leakage Current (output OFF): ≤0.1 mA
- Response Time: 1 ms (OFF→ON and ON→OFF)
- Isolation: Optical, per output point
- External Supply: 24 VDC required (output supply separate from PLC internal bus)
- Connector: 40-pin connector (requires Q-series connector assembly or terminal block adapter)
- Power Consumption: 5 VDC internal bus, approx. 0.09 A (plus external 24 VDC supply current)
- Operating Temperature: 0°C to 55°C
- Dimensions (W × H × D): 27.4 mm × 98 mm × 89.3 mm
- Weight: Approx. 0.10 kg
Typical Industrial Applications
The QY40P is the standard MELSEC-Q output module for European and international machine specifications requiring PNP source digital outputs for 24 VDC actuator control. In automotive body assembly lines where MELSEC-Q systems manage welding fixture clamps, part presence sensors, and tool positioning — all interfaced with 24 VDC PNP signals — the QY40P provides the 32-point PNP source output density required for comprehensive fixture control in a single module slot. Pharmaceutical production machinery with MELSEC-Q sequence controllers uses the QY40P for solenoid valve manifold control, pump relay activation, and process alarm indicator switching where the PNP sourcing interface is specified by the machinery standard (EN 61131-2 IEC type 1 and type 2 compatible). Building automation panels controlling HVAC damper actuators, fan motor contactors, and zone valve actuators via MELSEC-Q outputs specify the QY40P for the 32-point PNP source density — covering multiple HVAC zones from a single module. In semiconductor cleanroom automation where MELSEC-Q controls wafer handling equipment and process gas valve sequences, the QY40P’s solid-state transistor outputs (no relay contact wear) provide the high-reliability switching required for the frequent, repeated output state changes typical of automated semiconductor process equipment. Food and beverage filling lines where MELSEC-Q sequence PLCs control product flow valves, labelling actuators, and reject solenoids specify the QY40P for PNP source output compatibility with the European automation components (Festo, SMC, Parker valve manifolds) commonly used in food processing machinery.
Troubleshooting Guide
For QY40P outputs that activate when the PLC output device (Y address) is OFF, the most likely cause is output common wiring error — the QY40P’s external 24 VDC supply must be connected with the positive (+) terminal to the module’s external supply terminal and the negative (0 VDC) to the common terminal. Reversed supply polarity causes all 32 outputs to conduct regardless of the PLC output device state, as the transistors’ junction diodes conduct in the reverse direction when the supply polarity is reversed. Verify supply polarity with a voltmeter at the QY40P connector’s supply terminals before suspecting output transistor failure. For individual QY40P outputs that fail to activate (output OFF with PLC device ON), check the load resistance — the QY40P’s 0.1 A output current limit means loads with impedance above 240 Ω (at 24 VDC) will not receive enough current to activate reliably. Solenoid valves with 24 VDC coils typically draw 0.1–0.3 A (impedance 80–240 Ω) — if a solenoid valve is not activating, measure the coil resistance and verify the total load current is within the 0.1 A per-point limit. For QY40P outputs showing the SHORT LED indicator (short-circuit protection active), the connected load is drawing more than 0.1 A — the QY40P’s internal protection circuit activates when the output current exceeds approximately 0.15 A, disabling the output and activating the short-circuit indicator. Identify and disconnect the overloaded output, measure the load current, and if it exceeds 0.1 A specify an external relay driven by the QY40P output to switch the high-current load.
Frequently Asked Questions
Q: What is the maximum inductive load that can be connected directly to a QY40P output without an external suppression diode?
A: The QY40P includes internal output surge protection — an internal flyback suppression circuit across each output transistor absorbs the inductive voltage spike generated when solenoid valve coils, relay coils, and other inductive loads are de-energised. This internal suppression is rated for the QY40P’s standard inductive load applications (24 VDC solenoid valves and relay coils within the 0.1 A current limit). External suppression diodes across the load are not required for standard 24 VDC inductive loads within the current limit, but are recommended for high-inductance loads (large solenoids, electromagnets) where the stored energy at turn-off may exceed the internal suppressor’s rating.
Q: Can the QY40P source outputs drive NPN transistor inputs on step motor drivers?
A: Yes. The QY40P source (PNP) output sources 24 VDC to the load — connecting the QY40P output terminal to the step motor driver’s NPN (sink) input terminal, with the driver’s 0 VDC common connected to the QY40P’s external 0 VDC supply, provides the correct current flow through the step motor driver’s optocoupler input. The QY40P’s 0.1 A output is more than adequate for step motor driver pulse and direction inputs which typically require only 5–20 mA.
Q: What external supply specification is required for the QY40P, and can it share the 24 VDC supply with the QX80 input module’s sensor supply?
A: The QY40P requires an external 24 VDC supply (20.4–28.8 VDC) connected to the module’s external supply terminals to power the output transistors and the output load circuits. This external supply can be the same 24 VDC power supply used for the QX80 sensor supply, provided the supply has adequate current capacity for both the input sensor currents and the combined output load currents simultaneously. In systems where output loads draw significant current (multiple solenoid valves activated simultaneously), consider a dedicated 24 VDC supply for the QY40P outputs separate from the input sensor supply to prevent output load current causing voltage sag on the sensor supply circuit.
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