## Key Specifications

 

• Manufacturer: HEIDENHAIN
• Model Series: ERN 120
• Full Model Number: ERN 120 2048 03S12-03
• Identification Number (Id.Nr.): 377 101-8E
• Encoder Type: Incremental Rotary Encoder
• Resolution: 2048 lines/pulses per revolution
• Output Signal: TTL (Transistor-Transistor Logic). This typically corresponds to the RS-422 standard, providing differential square-wave signals for high noise immunity.
• Power Supply: 5 V DC (±10%)

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## Signal Output

 

As a TTL incremental encoder, this device provides the following signals:

• A and B Channels: Two square-wave signals that are 90 degrees out of phase with each other (quadrature). The control system uses these two signals to determine both the speed of rotation and the direction.
• R (Reference Mark): A single pulse that occurs once per revolution at a precise location. This is used for homing or finding a reference position.
• Differential Signals: For each channel (A, B, R), the encoder outputs two signals: the signal itself and its inverse (e.g., A and A’, B and B’). This differential transmission method is highly resistant to electrical noise, which is common in industrial environments.

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## Functionality and Application

 

The Heidenhain ERN 120 is an enclosed encoder with its own bearings, designed for robust performance. It is typically mounted directly onto the shaft of an electric motor.

When the motor shaft turns, the encoder generates a precise stream of electrical pulses. A drive controller (e.g., a servo drive) counts these pulses to track the exact position of the motor shaft and calculates their frequency to determine its speed. This closed-loop feedback allows for highly accurate control of motor position and velocity, which is essential in applications such as:

• CNC machine tools
• Robotics
• Printing presses
• Packaging machines

data sheet

Incremental Encoder RL32-0/1024ER.14KB