Product Details

Modicon A120 is the complete TSX Compact modular plc system and reliable modular programmable controller series developed by AEG Modicon, also widely known as the A120 automation rack family for legacy industrial automation. This full system platform includes CPU processors, discrete I/O cards, analog modules, communication adapters and rack power supplies, built around the dedicated A120 backplane bus, programmed by Modsoft software with LL984 ladder logic. The A120 series supports flexible configuration, users can mix and match I/O and specialty modules according to field signal demands, covering digital switching, analog measurement, high-speed counting and serial network communication. Some variants are designed for railway and heavy-duty vehicle control with enhanced shock and vibration resistance. The whole system adopts battery-backed RAM to retain program and register data through power loss, and supports Modbus, Modbus Plus and Modnet network links to connect HMI, remote racks and supervisory SCADA. With conformal coated circuit boards and industrial component grade, the A120 system can sustain continuous long-running operation in dusty, vibrating process environments. As a discontinued legacy spare platform, this a120 automation rack serves as a drop-in replacement system to restore full sequential and closed-loop automatic control for ageing Modicon TSX Compact automation installations.

Basic Parameters

Brand: Modicon (AEG / Schneider legacy)

Model: A120, TSX Compact A120 series

Product Type: Modular PLC Automation System

Compatible Backplane: Dedicated A120 TSX Compact rack backplane

Programming Software: Modsoft

Logic Language: LL984 Ladder Logic

Communication: Modbus RTU, Modbus Plus, Modnet options

Power Supply Options: AC 95–270 VAC or 20–30 VDC rack power

Memory: Battery-backed RAM, multiple CPU memory variants

Expandability: Support discrete, analog, counter and communication I/O modules

Indicator: Front LED for run, fault, network and channel status

Product Status: Discontinued, end of original production

Net Weight: Depends on rack configuration

Supported Functions

This tsx compact plc system executes cyclic ladder logic scanning for all installed CPU and I/O modules. The modular programmable controller supports timer, counter, arithmetic operation, comparison and PID closed-loop regulation for temperature, flow, pressure and liquid level. This a120 automation rack supports sequential batch control, alarm management and recipe storage, and can exchange real-time process data across legacy Modicon networks for interlock between multiple control stations. It runs comprehensive built-in self-diagnostics to detect memory corruption, bus error, communication dropout, I/O fault and low backup battery. When critical faults trigger, the system drives outputs to predefined safe states to protect field actuators and process equipment. It can pair with S908 remote I/O adapters to extend control signals to distributed field locations.

Core Functions

As a flexible modular programmable controller platform, this tsx compact plc system reads sensor and switch signals, executes custom user logic and sends switching and analog commands to field actuators. Its expandable rack design allows customized signal configuration for small to medium process skids, and its multi-network capability enables integration into existing legacy Modicon plant control networks. This a120 automation rack works as a direct spare system to rebuild complete automatic control for ageing Modicon TSX Compact automation racks.

Hardware Specifications & Environmental Features

Operating Temperature: 0°C ~ +60°C

Storage Temperature: -40°C ~ +85°C

Relative Humidity: 5%–95%, non-condensing

Housing: Modular single-slot modules within metal compact rack

Protection: Hardware watchdog, transient suppression, battery backup circuit

Anti-interference: Galvanic isolation, filtered communication ports, vibration reinforced design

Compatibility: Full lineup of A120 TSX Compact I/O, power and communication modules, Modbus compatible devices

Industry Applications: Applied in legacy petrochemical distributed control, old paper making production automation, material handling conveyor lines, packaging and textile machinery, water treatment remote signal collection and large conveyor remote I/O control racks.

Note: Confirm backplane type, CPU firmware version, program backup, battery condition and module compatibility before ordering.

This is from our current stock.

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