The Q52B is Mitsubishi Electric’s 5-slot main base unit for the MELSEC-Q programmable controller series, providing the physical mounting platform and internal power distribution bus for up to five peripheral modules alongside the CPU and power supply modules. As a compact main base unit, the Q52B is designed for space-constrained control panel installations where a small system footprint is a priority but a 3-slot Q3B base is insufficient for the required module count. In stock at Atlantech Drives. Request your quote within 24-48 hours with worldwide shipping and 12-month warranty.
What Is the Q52B?
The Q52B is a main base unit — not a CPU module or I/O module — forming the structural and electrical backbone of a MELSEC-Q system. It provides five module slots for peripheral modules (I/O, analogue, communication, positioning, or special function modules) plus dedicated slots for the power supply module (leftmost position) and CPU module (slot 0). The Q52B’s internal bus distributes 5 VDC power from the installed power supply module (Q61P, Q62P, or Q63P) to all peripheral modules and provides the high-speed MELSEC-Q internal bus for data exchange between the CPU and peripheral modules. The Q52B is a main base unit — it cannot be used as an extension base and cannot be connected to a CPU base via extension cable. For systems requiring more than five peripheral module slots, additional extension base units (Q6B, Q12B, Q25B) must be connected via a QC extension cable. All MELSEC-Q Universal model CPUs (Q03UDVCPU through Q26UDEHCPU) and all Q series power supply modules are compatible with the Q52B.
Key Technical Specifications
- Model: Q52B
- Type: Main base unit
- Number of Module Slots: 5 (peripheral modules only)
- Power Supply Slot: 1 (dedicated, leftmost)
- CPU Slot: 1 (dedicated, slot 0)
- Total Slots Including Power Supply and CPU: 7
- Internal Bus: MELSEC-Q high-speed internal bus
- Compatible Power Supply Modules: Q61P, Q61P-D, Q62P, Q63P, Q64P, Q61SP
- Compatible CPUs: All MELSEC-Q series CPU modules
- Extension Base Connection: Not supported (main base only)
- Operating Temperature: 0°C to 55°C
- Dimensions (W × H × D): 245 mm × 98 mm × 44.1 mm
- Weight: Approx. 0.41 kg
Typical Industrial Applications
The Q52B is commonly specified for compact machine-mounted control systems where panel space is at a premium. Typical applications include standalone conveyor drive controllers requiring one CPU, one power supply, two digital I/O modules, and one communication module — fitting exactly within the Q52B’s five peripheral slots without requiring an extension base. It is also widely used in remote I/O station builds where a MELSEC-Q CPU is used as an intelligent remote station master with a small local I/O count, and in laboratory and test equipment where a MELSEC-Q system must be integrated into a 19-inch rack enclosure with limited depth. In retrofit projects replacing obsolete MELSEC-A or MELSEC-AnS systems, the Q52B is frequently paired with an adapter module to maintain compatibility with existing field wiring termination blocks, minimising rewiring costs during the migration.
Installation Advice
When installing modules into the Q52B, always power down the system completely before inserting or removing modules — hot-swapping is not supported on standard MELSEC-Q base units and can cause damage to the internal bus connectors. Modules should be inserted straight into the slot with firm, even pressure until the front-panel locking tab clicks into the base unit rail. Do not apply lateral force during insertion. When selecting a power supply module for the Q52B, calculate the total 5 VDC current consumption of all installed modules (listed in each module’s hardware manual) and ensure the selected power supply module’s rated output current is not exceeded — overloading the power supply will cause the Q61P or Q62P to enter overcurrent protection and shut down the entire base. For DIN rail mounting, use the DIN rail mounting adapter (sold separately) and ensure the rail is securely fixed to the panel backplate with a maximum 220 mm span between rail fixing screws to prevent vibration-induced loosening in mobile or high-vibration environments.
Frequently Asked Questions
Q: Can the Q52B be used with a Q170MCPU motion controller?
A: Yes. The Q52B is compatible with the Q170MCPU and all other MELSEC-Q CPU modules. In a multi-CPU configuration with a Q170MCPU and a sequence CPU, both CPUs occupy CPU slots 1 and 2 respectively, leaving five slots for peripheral modules. Note that the Q170MCPU requires a dedicated SSCNET III/H servo network connection — the servo amplifier cables connect directly to the Q170MCPU module, not to a peripheral module in the base.
Q: What is the difference between the Q52B and the Q55B?
A: The Q52B provides 5 peripheral module slots while the Q55B provides 5 slots but with a different physical width to accommodate a specific panel layout requirement. Both are main base units compatible with the same CPU and power supply modules. The Q55B is selected when the panel layout requires a wider base unit spacing, while the Q52B is the more compact option for tight installations.
Q: Is the Q52B compatible with the older MELSEC-Q H-model CPUs such as the Q06HCPU?
A: Yes. The Q52B is compatible with all MELSEC-Q series CPU modules including H-model, Universal model, and Universal Enhanced model CPUs. The internal bus interface is identical across all MELSEC-Q generations, ensuring full backward and forward compatibility between base units and CPU modules.
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