Description

The A1S65B-S1 is a 5-slot extension base unit manufactured by Mitsubishi Electric for their MELSEC-A Series programmable logic controller (PLC) system. This robust mechanical assembly serves as a critical platform for expanding the I/O capacity and functionality of a MELSEC-A control system beyond the constraints of the main CPU base unit. The primary role of the Mitsubishi A1S65B-S1 is to provide the physical mounting, electrical backplane, and data communication pathway for up to five additional modules, such as digital I/O, analog I/O, communication interfaces, or special function cards. It connects to the main CPU unit or another extension base via a dedicated extension cable, creating a seamless and unified control architecture. Engineered for durability, the A1S65B-S1 features a sturdy metal construction that protects sensitive electronic modules from physical damage, vibration, and electromagnetic interference (EMI), ensuring signal integrity and reliable operation in harsh industrial environments. This unit is indispensable for designing scalable automation solutions that can grow with evolving process requirements.

A1S65B-S1 MITSUBISHI

Technical Specifications

Parameter Name	Parameter Value
Product Model	A1S65B-S1
Manufacturer	Mitsubishi Electric
Product Type	PLC Extension Base Unit
Number of Slots	5
Compatible Series	MELSEC-A Series
Compatible Modules	All A1S-series I/O and special function modules
Required Power Supply	Must be used with a separate A1S6□PN power supply module (e.g., A1S61PN, A1S62P)
Backplane Connector	5 V DC bus for module logic power (from power supply)
Extension Interface	Left-side port for connecting extension cable (e.g., A1SC03B, A1SC05B)
Material	High-strength steel casing
Mounting	DIN rail mountable (TS35 DIN rail) or direct panel mounting
Operating Temperature	0°C to 55°C
Storage Temperature	-25°C to 75°C

Main Features and Advantages

The Mitsubishi A1S65B-S1 extension base unit is defined by its robust construction and system integration capabilities. Its primary advantage is the significant enhancement of system scalability it provides. By adding one or more A1S65B-S1 units, engineers can dramatically increase the number of I/O points available to the CPU, accommodating large and complex machines without needing a larger, more expensive central controller. The base unit’s design ensures perfect alignment and secure connection for all modules, thanks to its precision-machined guides and high-quality connectors, which prevent connection failures that can lead to costly downtime.

The heavy-gauge steel enclosure offers superior shielding against electromagnetic interference, a critical feature for maintaining signal accuracy in environments with motor drives, welders, and other sources of electrical noise. The unit is designed for flexible installation, supporting both DIN rail mounting for compact control cabinets and direct panel mounting for added rigidity in high-vibration applications. The integration is seamless; when connected with the appropriate shielded extension cable, the A1S65B-S1 becomes a logical part of the main rack, with all modules automatically recognized by the CPU, simplifying system configuration and programming in Mitsubishi’s GX Developer software.

Application Field

The A1S65B-S1 is deployed in virtually any industrial automation application that utilizes the Mitsubishi MELSEC-A Series platform and requires more I/O capacity than the main base unit can provide. In automotive manufacturing, multiple A1S65B-S1 units are used to create distributed control nodes along a production line or assembly cell, handling the extensive I/O required for robots, sensors, and actuators. In large packaging machinery, they house the numerous analog and digital modules needed for precise motion control, temperature regulation, and vision system integration. Plastic injection molding machines use these extension bases to organize modules for barrel heating zones, hydraulic valve control, and peripheral handling equipment.

They are also fundamental in material handling systems, such as large conveyor networks and automated storage and retrieval systems (ASRS), where hundreds of sensors and motors need to be managed. Water treatment facilities employ them to scale their control systems for managing multiple pumps, valves, and analytical sensors across a large plant. Essentially, the A1S65B-S1 is the enabling hardware for building medium to large-scale control systems with the reliable and proven MELSEC-A Series architecture.

A1S65B-S1 MITSUBISHI

Related Products

A1S38B: A 8-slot main base unit that houses the CPU and power supply.

A1S35B: A 5-slot main base unit.

A1S61PN: A 100-240V AC input power supply module, required to power the A1S65B-S1 and its modules.

A1SC03B / A1SC05B / A1SC12B: Shielded extension cables of varying lengths (0.3m, 0.5m, 1.2m) to connect the base unit to the main CPU rack.

A1SX40: A typical 16-point DC input module that would be installed in the A1S65B-S1.

A1SY40: A typical 16-point relay output module.

A1SJCPU: A typical MELSEC-A Series CPU module that would be the system’s brain.