Mitsubishi A1SJ71QC24-R2 Serial Communications Module – MELSEC-A Series
Imagine a critical production line where your MELSEC-A series PLC needs to exchange real-time data with HMIs, SCADA systems, or peripheral devices — but the communications link is missing or failed. Without a dedicated serial communications module like the A1SJ71QC24-R2, your entire automation system becomes isolated: no remote monitoring, no data logging, no coordinated control. Downtime escalates, diagnostics become guesswork, and production losses mount by the hour. The A1SJ71QC24-R2 is not a peripheral accessory — it is the communications backbone that keeps your MELSEC-A system connected and operational.
The Mitsubishi A1SJ71QC24-R2 is a dedicated serial communications module designed for the MELSEC-A series compact PLC platform (A1S/A2S chassis). It provides RS-422/RS-485 multi-drop serial communication capability, enabling the CPU to interface with external devices using Mitsubishi’s established QC24 protocol framework. Within the global industrial automation market, the MELSEC-A series remains one of Mitsubishi Electric’s most widely deployed legacy PLC families, with millions of units still active in manufacturing, infrastructure, and process industries worldwide. The A1SJ71QC24-R2 is a key spare and replacement part for maintaining these systems at peak performance.
Technical Specifications
- Part Number / SKU: A1SJ71QC24-R2
- Manufacturer: Mitsubishi Electric
- Series: MELSEC-A (A1S Compact Series)
- Module Type: Serial Communications Module
- Interface: RS-422 / RS-485
- Communication Protocol: QC24 (MC Protocol compatible)
- Applicable CPU: A1SCPU, A1SHCPU, A2SCPU, A2SHCPU and compatible A1S series CPUs
- Mounting: A1S series base unit slot
- Weight: 420 g
- Condition Available: New, Refurbished, Used-Tested
Note: All specifications are based on Mitsubishi Electric official documentation. Konmask.com does not fabricate or modify technical parameters.
Key Features & Benefits
- RS-422/RS-485 Multi-Drop Support: Enables reliable long-distance serial communication in electrically noisy industrial environments.
- QC24 Protocol Compatibility: Seamlessly integrates with Mitsubishi’s MC Protocol ecosystem for standardized device communication.
- Compact A1S Form Factor: Designed specifically for the A1S series slim chassis — no adapter or conversion required.
- Proven Legacy Reliability: Engineered to Mitsubishi Electric’s industrial-grade standards, with a track record spanning decades of field deployment.
- Direct CPU Communication: Allows external devices (HMIs, PCs, barcode readers, drives) to read/write PLC data registers directly.
- Simplified Wiring: R2 variant provides straightforward RS-422 terminal block connectivity, reducing installation complexity.
Industry & Equipment Applications
- Automotive Manufacturing: Body assembly lines, welding robots, and conveyor control systems using MELSEC-A PLCs.
- Food & Beverage Processing: Packaging machines and filling lines requiring HMI-to-PLC serial data links.
- Semiconductor & Electronics: Wafer handling equipment and SMT production lines with legacy Mitsubishi control systems.
- Water Treatment & Utilities: SCADA-connected pump stations and filtration systems running MELSEC-A controllers.
- Textile & Printing Machinery: Multi-axis coordinated machines relying on serial communications for synchronization.
- Building Automation & Infrastructure: Elevator control panels and HVAC systems with Mitsubishi A-series PLCs.
System Integration & Compatible Parts
The A1SJ71QC24-R2 is designed to work within the broader MELSEC-A ecosystem. Compatible and commonly paired components include:
- CPU Modules: A1SCPU, A1SHCPU, A2SCPU, A2SHCPU
- Base Units: A1S38B, A1S52B, A1S55B, A1S58B
- Power Supply Modules: A1S61PN, A1S62PN
- Related Communications Modules: A1SJ71UC24-R4, A1SJ71QC24-R4, A1SJ71E71-B2
- Programming Software: GX Developer, GX Works2 (with A-series support)
Contact Konmask.com if you need assistance identifying compatible system components for your specific application.
Our Quality Assurance Process
Every Mitsubishi A1SJ71QC24-R2 unit sourced and supplied by Konmask.com undergoes a rigorous multi-stage quality process:
- Visual Inspection: Checking for physical damage, corrosion, bent pins, and label integrity.
- Functional Verification: Power-on testing and communication port diagnostics where applicable.
- Authenticity Check: Cross-referencing part markings, date codes, and manufacturer labels against known genuine specifications.
- Secure Packaging: Anti-static packaging with moisture barrier protection for safe international shipping.
- Documentation: Test reports and inspection records available upon request for critical procurement.
How to Order
- Submit an inquiry via the Contact Us page or email support@konmask.com with your required quantity and delivery timeline.
- Our technical team will confirm availability, condition, and provide a formal quotation within 1 business day.
- Upon order confirmation, we arrange secure packaging and international shipping with full tracking.
- Post-delivery support is available for installation guidance and compatibility verification.
Why Choose Konmask.com?
- Industrial Automation Specialists: We focus exclusively on PLC, DCS, and automation hardware — not a generalist marketplace.
- Global B2B Supply: Serving maintenance engineers, system integrators, and procurement teams across Asia, Europe, and the Americas.
- Legacy Parts Expertise: Deep inventory and sourcing network for discontinued and hard-to-find Mitsubishi MELSEC-A components.
- Fast Response: Dedicated account managers respond to inquiries within 24 hours.
- Transparent Quality: Honest condition grading — we clearly state whether parts are new, refurbished, or used-tested.
Frequently Asked Questions
- Q: Is the A1SJ71QC24-R2 still in production by Mitsubishi Electric?
- A: The MELSEC-A series has been discontinued by Mitsubishi Electric. However, Konmask.com maintains sourcing channels for genuine new-old-stock and quality-tested used units to support ongoing maintenance needs.
- Q: What is the difference between A1SJ71QC24-R2 and A1SJ71QC24-R4?
- A: The R2 variant uses RS-422 interface, while the R4 variant uses RS-232C interface. Selection depends on your external device’s communication port type and wiring distance requirements.
- Q: Can this module communicate with non-Mitsubishi devices?
- A: Yes. Using Mitsubishi’s MC Protocol (formerly MELSEC Communication Protocol), the A1SJ71QC24-R2 can interface with third-party HMIs, PCs, and devices that support RS-422/RS-485 serial communication.
- Q: Do you provide a warranty on this part?
- A: Warranty terms vary by unit condition (new vs. used-tested). Please contact us for specific warranty details applicable to your order.
- Q: How long does international shipping take?
- A: Typical delivery is 5–10 business days for most destinations via DHL/FedEx express. Expedited options are available upon request.
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