Mitsubishi Q04UDEHCPU MELSEC-Q Universal CPU, 40k Steps

Q04UDEHCPU Universal model Q-series CPU, decoded

The Mitsubishi Q04UDEHCPU is a MELSEC-Q Universal model sequence CPU module with 40k steps of program capacity, a built-in Ethernet port, a USB port and an LD instruction time of 9.5 ns. The name reads as follows: Q is the MELSEC-Q platform, 04 is the program size class (40k steps), UD marks the Universal model, E means built-in Ethernet and H the high-performance type, and CPU is the module type. The smallest of the high-performance UDEH processors that still brings the full Universal model feature set. It suits a single-rack machine or a compact process skid where program size is modest but the built-in Ethernet port and 4096-point I/O ceiling are still wanted.

Seven Star LLC supplies the Q04UDEHCPU in Oman and the GCC as an independent supplier in Muscat, not affiliated with the manufacturer. The figures on this page come from the manufacturer’s product data and selection guide.

Q04UDEHCPU technical specifications

Memory sizes follow the manufacturer’s selection guide: the Q04UDEHCPU has 160 kB of program memory for 40k steps. Communications supported by the built-in port include program upload and download, remote monitoring and maintenance, HMI connection, an FTP server and SNTP time synchronization.

How the Q04UDEHCPU executes and communicates

The CPU runs a stored-program cyclic scan: inputs are refreshed, the sequence program is executed, and outputs are refreshed, with direct access available where a faster response is required. Backed-up device memory and the clock are held by the battery, so the battery must be checked as part of routine maintenance.

The built-in Ethernet port provides 16 connections shared between MELSOFT engineering access and MC protocol, plus one FTP connection. This lets a SCADA, HMI or historian read device data without an extra network module, while engineering software connects over the same port or over USB.

Where the Q04UDEHCPU fits in a MELSEC-Q system

The CPU sits in the CPU slot of a Q main base and works with the Q-series power supplies, digital and analog I/O, positioning, counter and network modules. In multi-CPU configurations on the high-speed base units (Q35DB, Q38DB, Q312DB) a Universal CPU can be the first CPU alongside motion, robot, CNC or C-language CPUs. Sibling processors in the same family include the Q03UDVCPU, Q04UDVCPU, Q06UDVCPU, Q13UDVCPU and Q26UDVCPU (UDV type) and the Q04UDEHCPU, Q13UDEHCPU and Q50UDEHCPU (UDEH type).

Choose it when an existing system already runs a Q03UDE or Q04UDEH and a like-for-like spare is needed, or when the application logic sits comfortably inside 40k steps. If the program has grown, step up to the Q13UDEHCPU or Q50UDEHCPU instead of squeezing the memory.

Lifecycle and availability

The manufacturer lifecycle listing for Q04UDEHCPU shows end-of-life on 12.01.2024, last time buy on 30.08.2026 and end of support on 31.10.2033. That means new stock is limited and surplus or remaining inventory is the realistic source, so confirm availability early and plan a migration path to the iQ-R series for long-lived plants.

Selection and ordering checklist for the Q04UDEHCPU

• Confirm the exact model and suffix on the nameplate: Q04UDEHCPU is not interchangeable with other sizes without a program size check.
• Compare program size: 40k steps here, against the project size shown in the engineering software.
• Check the 5 VDC load of the whole base against the power supply rating; this CPU draws 0.39 A.
• Decide whether a memory card is needed for logging, parameters or program storage.
• Confirm firmware and serial number prefix when the CPU is a spare for a validated installation.
• Request the battery type and replacement interval that your maintenance plan expects.

Installation, commissioning and maintenance

Mount the Q04UDEHCPU in the CPU slot of the main base with the power off, fit the backup battery supplied or specified for the system, and connect engineering software over USB or Ethernet. After downloading the project, set the clock, verify the parameters for I/O assignment and check the error history for any latched alarms.

For service, keep a documented project backup, a spare battery and, where downtime is costly, a spare CPU of the same model. Replace the battery on a fixed schedule, because data held in battery-backed memory can be lost if the battery runs flat while the system is powered down.

Typical applications in Oman and the GCC

Q-series CPUs of this class are installed in water treatment and desalination plants, power and utility switchgear, oil and gas auxiliaries, and food and packaging lines across Oman and the GCC. Cabinets in these regions see high ambient temperature, dust and humidity, so the CPU should live in a ventilated, clean cabinet with dust-filtered airflow.

The Q04UDEHCPU is commonly bought as a spare to keep an existing Q-based installation running rather than for new designs, because the Q platform has entered its lifecycle phase-out and the iQ-R series is the manufacturer’s forward path.

Q04UDEHCPU within the Universal model family

Information to send with an RFQ

• Part number Q04UDEHCPU and quantity
• Nameplate photo including serial number and firmware version for spares
• Base unit and power supply model in the existing rack
• Required condition and any traceability or packing requirements
• Delivery location in Oman or the GCC and required lead time

Documents and quotation

A Mitsubishi selection guide covering the Q-series CPU line is attached on this page and lists the memory, speed and communication data used here. For wiring, installation and instruction details, refer to the manufacturer’s manuals for the Universal model QCPU.

Send the Q04UDEHCPU part number, quantity and delivery location and Seven Star LLC will confirm availability and send a quotation.