Incremental Encoder vs Pulse Encoder: Key Differences

Encoders are widely used in motion control systems to measure position and speed. Incremental encoders and pulse encoders differ significantly in measurement methods, accuracy, and output signals.

1. Measurement method

Incremental encoders generate signals based on relative motion. They convert motion into electrical pulses and measure movement by counting pulses. Typical incremental designs use two channels, A and B, to indicate direction and distance.

Pulse encoders use non-contact sensors such as photodetectors to read slots or markings on a rotating element. These produce a waveform sequence that yields angular displacement and direction, and generate a cumulative position count as rotation proceeds.

2. Measurement accuracy

Incremental encoder resolution depends on pulse count and typically yields lower absolute resolution compared with some pulse encoders, but they support high-speed rotation and are robust. Pulse encoders can offer very high resolution, potentially at submicron levels, but may accumulate counting errors over time.

3. Output signals

Incremental encoders output relative signals that require integration by a counter to obtain absolute position. Pulse encoders can provide absolute position directly without counter integration, simplifying position feedback.

The two encoder types also differ in construction. Incremental encoders are often simpler, while pulse encoders can include fixed and rotating parts plus read heads, making them more complex.

Choosing between them depends on application needs for speed, resolution, and absolute position requirements.