Product Details

MODICON 121-108-306 is an industrial servo amplifier and high-performance motion controller for legacy Modicon motion control systems, functioning as a precise drive unit to power compatible brushless servo motors. It receives position, speed and torque setpoints from the upper motion processor and converts digital control commands into regulated power output to realize stable closed-loop motion control. The unit continuously captures incremental encoder feedback signals, compares actual position and velocity against target values, and dynamically adjusts its output to deliver accurate positioning and smooth running for automated cutting, feeding and material handling machinery. Front-mounted status LEDs clearly indicate power ready, drive enable, fault alarm and feedback signal status, allowing maintenance technicians to rapidly diagnose typical faults such as overcurrent, overvoltage, encoder loss and overheating on site. Integrated EMI filtering and surge suppression circuits protect the internal power stage and feedback port against electromagnetic interference and transient voltage spikes produced by inverters, contactors and heavy power cables inside electrical enclosures. Users can tune acceleration, deceleration, control gain and safety limit parameters through dedicated Modicon motion configuration software. As an obsolete industrial spare part, this servo amplifier is widely used for replacement and maintenance of aging motion racks on production lines. Direct drop-in replacement keeps the original motor wiring, encoder wiring and motion parameter settings unchanged, greatly lowering commissioning workload and reducing production downtime.

Basic Parameters

Product type: servo amplifier drive

Part number: 121-108-306

Brand: Modicon

Control mode: closed-loop torque, speed and position control

Feedback: incremental encoder interface

Output: regulated power for brushless servo motor

Interface: command input, encoder feedback, motor power terminal

Cooling: forced air cooling

Protection: overcurrent, overvoltage, overheat and stall protection

Mounting: panel mounting inside control cabinet

Operating temperature: 0°C ~ +60°C

Protection grade: IP20

Supported Functions

Power amplification for brushless servo motor operation

Closed-loop regulation based on encoder feedback signals

Dynamic adjustment of torque, speed and position

Multi-type fault detection and fault signal output

Enable and stop control from host motion controller

Noise filtering and surge protection for power and signal loops

Core Functions

Serve as a reliable servo amplifier for legacy motion control systems

Visual LED indication for fast drive and feedback troubleshooting

Act as a stable motion controller for continuous manufacturing equipment

Work as a dependable drive unit for high-precision automated positioning

Modular replacement for discontinued Modicon motion hardware

Provide repeatable motion performance for critical production processes

Hardware Specifications & Environmental Features

Construction: integrated power board and control logic assembly

Storage temperature: -25°C ~ +70°C

Relative humidity: 5% to 95% non-condensing

Condition: obsolete original spare part, available stock

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 matched servo motor specification, encoder type, rated power and cabinet ventilation condition before ordering.

This is from our current stock.

available stock.xlsx