Two Powerful PLC Platforms, Different Strengths
Mitsubishi Electric offers two leading PLC platforms for factory automation: the MELSEC FX5U compact PLC and the MELSEC iQ-R modular PLC. Both are excellent choices, but they serve different needs. Understanding their differences will help you invest wisely and avoid over-engineering or under-specifying your automation system.
MELSEC FX5U: The Compact Powerhouse
The FX5U is Mitsubishi's flagship compact PLC, designed to deliver high performance in a small footprint. It is ideal for standalone machines and small to medium automation systems.
- Processing speed: 34 ns per logic instruction, making it one of the fastest compact PLCs available
- Built-in features: Ethernet, RS-485, up to 4 high-speed counters (200 kHz), and 4 pulse outputs
- I/O capacity: Up to 256 I/O points with expansion modules
- Motion control: Built-in positioning for up to 4 axes (simple positioning) without additional modules
- Programming: GX Works3 software with structured programming (ST, FBD, ladder)
- Best for: Packaging machines, small conveyor systems, standalone equipment, water treatment stations, and textile machinery
MELSEC iQ-R: The Modular Platform
The iQ-R series is Mitsubishi's high-end modular PLC platform, built for large-scale, complex automation systems that demand maximum flexibility and performance.
- Processing speed: 0.98 ns per logic instruction, roughly 35 times faster than the FX5U
- I/O capacity: Up to 16,384 I/O points across multiple racks
- Redundancy: Supports CPU redundancy and network redundancy for mission-critical applications
- Multi-CPU: Run multiple CPUs (PLC, motion, robot, CNC) on a single backplane
- Security: Built-in cybersecurity features including IP filtering and communication encryption
- Best for: Large production lines, cement plants, power stations, water treatment facilities, and multi-process manufacturing
Head-to-Head Comparison
| Feature | FX5U | iQ-R |
|---|---|---|
| Form Factor | Compact (all-in-one) | Modular (rack-based) |
| Processing Speed | 34 ns/instruction | 0.98 ns/instruction |
| Max I/O | 256 points | 16,384 points |
| Program Capacity | 128K steps | 800K steps |
| Ethernet | 1 port built-in | 2 ports built-in |
| Motion Axes | Up to 4 (simple) | Up to 256 (advanced) |
| Redundancy | No | Yes |
| Price Range (BDT) | 45,000 - 120,000 | 180,000 - 800,000+ |
Which Should You Choose?
Choose the FX5U if: You need a cost-effective solution for standalone machines, small production lines, or applications with fewer than 256 I/O points. The FX5U is perfect for most small and medium factories in Bangladesh.
Choose the iQ-R if: You are building a large-scale automation system, need redundancy for critical processes, require high-speed motion control for many axes, or plan to integrate multiple subsystems (PLC + motion + robot) on one platform.
Not sure which platform fits your project? Contact SISL's automation engineers for a free consultation. We will assess your requirements and recommend the most cost-effective solution, backed by our 17+ years of experience with Mitsubishi Electric systems in Bangladesh.
