The QX60 is Mitsubishi Electric’s 16-point high-voltage AC digital input module for the MELSEC-Q programmable controller series, accepting 200–240 VAC signals directly from field devices without requiring external signal converters — designed for European, Australian, and Asian industrial installations where 230 VAC is the standard control circuit voltage for pushbuttons, limit switches, relay contacts, and process switches. As the 200–240 VAC counterpart to the QX50 (100–120 VAC), the QX60 enables MELSEC-Q systems to interface directly with 230 VAC field instrumentation, avoiding the cost and complexity of intermediate signal conditioning relays or DC power supplies in high-voltage AC control environments. Available now at Atlantech Drives with worldwide express delivery and 12-month warranty — complete our quote form for pricing and availability.
What Is the QX60?
The QX60 is a MELSEC-Q series AC digital input module providing 16 input points in a single common group, each capable of accepting 200–240 VAC field signals. Like the QX50, the QX60 rectifies and filters the AC input signal internally before transmitting the resulting logic level to the CPU via the MELSEC-Q high-speed internal bus. Optical isolation rated at 2,500 VAC between the 200–240 VAC field side and the 5 VDC internal bus provides robust protection against AC line transients, ground faults, and high-voltage disturbances in the field wiring infrastructure. The QX60 is particularly well suited for retrofit projects in European manufacturing facilities where MELSEC-A or MELSEC-AnS systems with AX60 or A1SX60 AC input modules are being migrated to MELSEC-Q, allowing the existing 230 VAC field wiring to be connected directly to the QX60 without rewiring.
Key Technical Specifications
- Model: QX60
- Input Points: 16
- Rated Input Voltage: 200–240 VAC (50/60 Hz)
- Operating Input Voltage Range: 170–264 VAC
- Input Current: Approx. 7 mA per point at 200 VAC, 10 mA at 240 VAC
- ON Voltage: 150 VAC minimum
- OFF Voltage: 60 VAC maximum
- Input Response Time: 25 ms (ON), 25 ms (OFF)
- Isolation: Optical, 2,500 VAC between field and internal bus
- Common Configuration: 16 points per common (1 common)
- Connector Type: 40-pin FCN connector
- Current Consumption (5 VDC internal bus): 0.25 A
- Operating Temperature: 0°C to 55°C
- Weight: Approx. 0.20 kg
Architecture & Design Overview
The QX60’s internal signal processing architecture follows Mitsubishi’s standard MELSEC-Q AC input module design: the 200–240 VAC field signal passes through a current-limiting resistor network before reaching the photodiode of an optical isolator, which converts the AC voltage signal to a logic-level DC signal on the internal bus side. The rectification and filtering circuit ensures that the module correctly detects both positive and negative half-cycles of the AC waveform, providing reliable ON detection across the full 170–264 VAC operating range. A dedicated noise filter stage suppresses high-frequency transients (such as those generated by contactor coil switching or nearby variable frequency drives) that could cause false input triggering on sensitive points. The optical isolation stage’s 2,500 VAC withstand rating exceeds the IEC 61131-2 requirement for Type 3 digital inputs, ensuring compliance with international PLC safety standards. All 16 input points share a single common terminal — the common terminal carries the return path of the 200–240 VAC supply for the input field devices, and must be correctly wired to the neutral conductor of the AC supply feeding the field devices to ensure proper circuit operation and personnel safety.
Expert Tips
When installing the QX60 in a panel alongside 24 VDC modules, route the 200–240 VAC field wiring in a separate cable duct from the 24 VDC signal wiring to prevent capacitive coupling between the high-voltage AC conductors and the low-voltage DC signal wires — 230 VAC field wiring run in parallel with 24 VDC sensor cables over distances greater than 1 metre can induce sufficient noise to cause false triggering on adjacent DC input modules. Use shielded cable for any 230 VAC field wiring runs longer than 10 metres, with the shield connected to protective earth at the panel end only (single-point earthing) to avoid earth loops. For the QX60’s common terminal, use a wire cross-section of at least 1.5 mm² — the common carries the return current for all 16 input points simultaneously, and undersized common wiring can develop a measurable voltage drop that reduces the effective input voltage at the module below the 150 VAC minimum ON threshold on distant field devices. When performing insulation resistance testing (meggering) on the panel field wiring, disconnect the QX60’s FCN connector before applying the test voltage — the QX60’s optical isolator input circuit is not rated for the high DC voltage (typically 500 VDC or 1,000 VDC) applied during insulation resistance tests, and applying megger voltage with the module connected will permanently damage the input optocouplers.
Frequently Asked Questions
Q: Can the QX60 be used on a 400 VAC three-phase system by connecting phase-to-neutral (230 VAC)?
A: Yes, provided the phase-to-neutral voltage is within the QX60’s 170–264 VAC operating range. In a 400 VAC three-phase system with a solidly earthed neutral, the phase-to-neutral voltage is 230 VAC — directly within the QX60’s rated input range. Connect the field device between the phase conductor and neutral, with the QX60’s input common terminal connected to neutral. Never connect the QX60’s input common terminal to a phase conductor, as this would expose the module’s internal circuitry to 400 VAC phase-to-phase voltage, which exceeds the module’s isolation rating.
Q: What is the difference between the QX60 and the QX50, and how do I select the correct module for a retrofit project?
A: The QX60 is rated for 200–240 VAC input (European standard), while the QX50 is rated for 100–120 VAC (North American standard). For a retrofit project, identify the control circuit voltage used in the original panel: if field devices are wired to 120 VAC, specify QX50; if wired to 230 VAC, specify QX60. In some international installations, both voltage levels coexist in the same panel — use a combination of QX50 and QX60 modules assigned to the respective field circuit zones.
Q: Does the QX60 require any special GX Works2 parameter settings compared to a standard 24 VDC input module?
A: No special parameters are required. In GX Works2’s I/O assignment, the QX60 is configured as a standard 16-point digital input module (module type: QX60). The input filter time setting defaults to 25 ms and cannot be reduced below this value for AC input modules — this is a hardware constraint of the AC input circuit, not a software parameter, and applies regardless of GX Works2 settings.
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