Mitsubishi A1S68B – 8-Slot PLC Expansion Base Unit | MELSEC-A Series Platform
Engineering Background
The Mitsubishi Electric MELSEC-A Series established itself as a cornerstone of industrial automation infrastructure across Asia-Pacific and global manufacturing facilities throughout the 1980s–2000s. Designed for high-density I/O expansion in demanding process and discrete manufacturing environments, the A1S68B expansion base unit continues to serve as a critical component in legacy system maintenance, brownfield upgrades, and long-lifecycle control architectures.
Product Positioning
The A1S68B is an 8-slot expansion base unit engineered to extend the I/O capacity of MELSEC-A Series PLC systems. It connects to the main base unit via the dedicated extension cable, enabling procurement engineers and system integrators to scale control capacity without full system replacement. Konmask.com supplies verified OEM units to support MRO (Maintenance, Repair & Operations) and capital project requirements globally.
Complete Technical Specifications
| Parameter | Specification |
|---|---|
| Model Number | A1S68B |
| Manufacturer | Mitsubishi Electric Corporation |
| Series / Platform | MELSEC-A Series |
| Unit Type | Expansion Base Unit (I/O Rack) |
| Number of Expansion Slots | 8 slots |
| Compatible CPU Modules | A1S Series CPU (A1SCPU, A1SHCPU, A1SJHCPU, etc.) |
| Extension Connection | Dedicated A-Series extension cable (AC10B / AC30B) |
| Power Supply Slot | Dedicated power supply slot (left-side, not counted in 8 I/O slots) |
| Mounting | DIN rail or panel mount |
| Operating Temperature | 0°C to 55°C |
| Storage Temperature | -20°C to 75°C |
| Relative Humidity | 5% to 95% RH (non-condensing) |
| Vibration Resistance | IEC 61131-2 compliant |
| Unit Weight | Approx. 4,460 g (with power supply) |
| Compliance | CE, UL (per original OEM certification) |
| Country of Origin | Japan |
Proven Application Environments
- Automotive Manufacturing: Body assembly lines, paint shop conveyors, and press control systems requiring high I/O point counts.
- Food & Beverage Processing: Bottling lines, packaging machinery, and batch process control with multi-zone I/O distribution.
- Semiconductor & Electronics Fabrication: Cleanroom equipment control and wafer handling systems with legacy MELSEC-A infrastructure.
- Water Treatment & Utilities: Pump station control, SCADA-integrated I/O expansion for distributed field devices.
- MRO & Brownfield Upgrades: Direct drop-in replacement for existing A1S68B units in operational facilities avoiding full system migration costs.
Engineering Advantages
- 8-Slot High-Density Expansion: Maximizes I/O density per rack, reducing cabinet footprint and wiring complexity.
- Seamless MELSEC-A Compatibility: Full backward compatibility with all A1S-series I/O modules, special function modules, and power supply units.
- Robust Industrial Construction: Designed to IEC 61131-2 environmental standards for vibration, shock, and temperature extremes.
- Scalable Architecture: Multiple A1S68B units can be cascaded via extension cables to achieve large-scale I/O configurations.
- Long-Lifecycle Support: Enables continued operation of proven MELSEC-A systems, deferring costly full-system replacement.
System Architecture & Signal Flow
The A1S68B integrates into the MELSEC-A system architecture as follows:
- Main Base Unit (A1S38B / A1S52B / A1S55B) → Extension Cable (AC10B/AC30B) → A1S68B Expansion Base
- The CPU module in the main base unit communicates with all I/O modules installed in the A1S68B via the internal bus extension.
- Each slot in the A1S68B accepts standard A1S-series I/O modules (digital input, digital output, analog, communication, etc.).
- A dedicated power supply module (e.g., A1S61P, A1S62P) must be installed in the power supply slot of the A1S68B to power the expansion rack independently.
- Maximum extension distance and number of expansion racks are governed by the CPU module specifications — consult the MELSEC-A Hardware Manual (IB-66712) for system configuration limits.
Sourcing & Quality Verification
- OEM Origin: All A1S68B units supplied by Konmask.com are sourced from verified OEM channels and authorized industrial distributors.
- Pre-Shipment Inspection: Each unit undergoes visual inspection for physical integrity, connector condition, and label authenticity prior to dispatch.
- Traceability: Batch and serial documentation available upon request for quality-critical procurement.
- Packaging: Anti-static protective packaging with foam cushioning for safe international transit.
- Warranty: 12-month limited warranty against manufacturing defects. Contact [email protected] for warranty claims.
Procurement Process
- Submit Inquiry: Contact [email protected] or call +0086 19859288691 with your required quantity and delivery timeline.
- Quotation: Receive a formal quotation within 1 business day including unit price, lead time, and shipping options.
- Order Confirmation: Place order via this product page or via purchase order (PO) for B2B accounts.
- Quality Check & Dispatch: Units are inspected and dispatched within 1–3 business days. Tracking provided upon shipment.
- Delivery: Global shipping via DHL, FedEx, or UPS Express. Estimated transit: 3–7 business days internationally.
- After-Sales Support: Technical support available post-delivery for installation verification and compatibility queries.
Technical FAQ
Q: Is the A1S68B compatible with MELSEC-Q or iQ-R series CPUs?
A: No. The A1S68B is exclusively compatible with MELSEC-A Series CPUs. It is not compatible with Q-series or iQ-R series systems without a full hardware migration.
Q: How many A1S68B expansion bases can be connected to one CPU?
A: The maximum number of expansion bases depends on the specific CPU model. Refer to the MELSEC-A Hardware Manual (IB-66712) for your CPU’s configuration limits. Typically up to 7 extension bases are supported.
Q: Does the A1S68B require its own power supply?
A: Yes. A dedicated A1S-series power supply module (e.g., A1S61P or A1S62P) must be installed in the power supply slot of the A1S68B expansion base.
Q: What extension cable is required to connect the A1S68B to the main base?
A: The AC10B (1m) or AC30B (3m) extension cables are used. Cable length selection depends on physical cabinet layout requirements.
Q: Can Konmask.com provide a Certificate of Conformance (CoC) or test report?
A: Yes. Documentation packages including CoC and inspection reports are available upon request for quality-critical procurement. Contact [email protected].
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Contact: [email protected] | +0086 19859288691
