Implementing 3-Switch XOR Ladder Logic with Internal Bit
Implement a 3-SPST switch XOR light circuit in LogixPro or RSLogix 500 using an internal relay bit. Includes truth tables, boolean equations, and verified.
Engineered for high-density, multi-disciplinary industrial control applications, the Mitsubishi Electric Q26UDEHCPU is an industrial-grade central processing unit designed for the MELSEC Q Series automation platform. This module integrates a built-in Ethernet port, enabling high-speed data transmission and seamless communication across factory networks. Featuring a highly optimized execution engine, it handles complex arithmetic, sequence controls, and structured text configurations with exceptional speed. Its physical design fits directly onto standard Q Series base units, making it ideal for systems requiring intensive calculations, multi-CPU coordination, and deep memory capacities.
| Specification Parameter | Value / Rating |
|---|---|
| Manufacturer | Mitsubishi Electric |
| Model / Article Number | Q26UDEHCPU (217902) |
| Control Method | Stored program iteration operation |
| I/O Control Method | Refresh method (Direct access I/O possible via DX/DY commands) |
| LD Instruction Speed | 9.5 ns |
| Program Capacity | 260 K steps (1040 KB) |
| Standard RAM / ROM | 1280 KB / 4096 KB |
| Ethernet Port Speed | 100/10 Mbps (Full / Half Duplex) |
| Internal Current Consumption (5 VDC) | 0.49 A |
| Operating Temperature Range | 0 to 55 degC |
| Storage Temperature Range | -25 to 75 degC |
| Relative Humidity | 5 to 95% RH (Non-condensing) |
| Dimensions (H x W x D) | 98 mm x 27.4 mm x 115 mm |
| Net Module Weight | 0.22 kg |
| Shipping Weight (Calculated) | 1.2 kg |
| Interface Type | Connector / Format | Function / Communication Standard |
|---|---|---|
| Ethernet Port | RJ45 | 100Base-TX/10Base-T, MC Protocol, FTP Server, Socket Interface |
| USB Port | Mini-B (USB 2.0 High Speed) | Direct PC programming connection (GX Works2 / GX Developer) |
When migrating to the Q26UDEHCPU from legacy non-universal hardware such as the Q25HCPU, engineering configurations must be updated in GX Works2. Universal models use a distinct memory organization structure (Standard RAM Drive 3 is handled differently). Additionally, confirm that any installed extension base units support the high-speed bus interfaces associated with Universal CPUs to prevent bus latency errors.
This CPU draws 0.49 A from the 5 VDC internal power rail. When configuring multiple CPUs or high-density network modules on a single rack (e.g., combining this CPU with multiple Ethernet/CC-Link IE units), perform a rigorous current consumption calculation. Standard power supplies like the Q61P may approach their operational limit, requiring an upgrade to high-capacity options such as the Q63P or Q64PN.
To maintain maximum throughput on the built-in Ethernet port, avoid routing communication patch cords parallel to motor lines or high-voltage lines. Always use Category 5e Shielded Twisted Pair (STP) cabling. If the Ethernet connection drops or times out under heavy factory floor noise, check that the ground terminal (LG/FG) on the main power supply module is securely tied to a dedicated Class D ground.
Global Express Shipping
Returns & Warranty

Engineered for high-density, multi-disciplinary industrial control applications, the Mitsubishi Electric Q26UDEHCPU is an industrial-grade central processing unit designed for the MELSEC Q Series automation platform. This module integrates a built-in Ethernet port, enabling high-speed data transmission and seamless communication across factory networks. Featuring a highly optimized execution engine, it handles complex arithmetic, sequence controls, and structured text configurations with exceptional speed. Its physical design fits directly onto standard Q Series base units, making it ideal for systems requiring intensive calculations, multi-CPU coordination, and deep memory capacities.
| Specification Parameter | Value / Rating |
|---|---|
| Manufacturer | Mitsubishi Electric |
| Model / Article Number | Q26UDEHCPU (217902) |
| Control Method | Stored program iteration operation |
| I/O Control Method | Refresh method (Direct access I/O possible via DX/DY commands) |
| LD Instruction Speed | 9.5 ns |
| Program Capacity | 260 K steps (1040 KB) |
| Standard RAM / ROM | 1280 KB / 4096 KB |
| Ethernet Port Speed | 100/10 Mbps (Full / Half Duplex) |
| Internal Current Consumption (5 VDC) | 0.49 A |
| Operating Temperature Range | 0 to 55 degC |
| Storage Temperature Range | -25 to 75 degC |
| Relative Humidity | 5 to 95% RH (Non-condensing) |
| Dimensions (H x W x D) | 98 mm x 27.4 mm x 115 mm |
| Net Module Weight | 0.22 kg |
| Shipping Weight (Calculated) | 1.2 kg |
| Interface Type | Connector / Format | Function / Communication Standard |
|---|---|---|
| Ethernet Port | RJ45 | 100Base-TX/10Base-T, MC Protocol, FTP Server, Socket Interface |
| USB Port | Mini-B (USB 2.0 High Speed) | Direct PC programming connection (GX Works2 / GX Developer) |
When migrating to the Q26UDEHCPU from legacy non-universal hardware such as the Q25HCPU, engineering configurations must be updated in GX Works2. Universal models use a distinct memory organization structure (Standard RAM Drive 3 is handled differently). Additionally, confirm that any installed extension base units support the high-speed bus interfaces associated with Universal CPUs to prevent bus latency errors.
This CPU draws 0.49 A from the 5 VDC internal power rail. When configuring multiple CPUs or high-density network modules on a single rack (e.g., combining this CPU with multiple Ethernet/CC-Link IE units), perform a rigorous current consumption calculation. Standard power supplies like the Q61P may approach their operational limit, requiring an upgrade to high-capacity options such as the Q63P or Q64PN.
To maintain maximum throughput on the built-in Ethernet port, avoid routing communication patch cords parallel to motor lines or high-voltage lines. Always use Category 5e Shielded Twisted Pair (STP) cabling. If the Ethernet connection drops or times out under heavy factory floor noise, check that the ground terminal (LG/FG) on the main power supply module is securely tied to a dedicated Class D ground.
Global Express Shipping
Returns & Warranty
Orders are processed and delivered Monday-Friday (excluding public holidays).
For full eligibility, restocking fees, and international return details, please view our official Refund & Return Policy .
| Country of origin |
United States
|