NEWS Technical Knowledge Base

Technical Knowledge Base

Nov.10,2025

Incremental vs. Absolute — Understand both encoder features at a glance

Incremental vs. Absolute

Understand both encoder features at a glance

TL;DR — Quick Tech Notes

Comparison	Incremental	Absolute
Power-off memory	Like a goldfish — 0%	Like an elephant — 100%
Homing	Must return to zero on every startup	Knows its position instantly at power-on
Signal type	A/B phase + Z index pulse	Gray Code、SSI、BiSS
Resolution vs. cost	High resolution, budget-friendly	Higher bit = higher cost
Multi-turn capability	Single-turn only, needs external counter	Single-turn or built-in multi-turn (mechanical/electronic)
Typical application	Motor speed feedback, wheel tracking	Elevators, cobots, safety drives

01 Core Concept — What are they actually measuring?

Incremental Encoder

Measures changes in motion. Each step generates A/B pulse signals; phase difference indicates direction, and Z gives one index reference per turn.
Power loss = data loss, so homing is required after reboot.

Example model：HS30F

Learn more ◆

Absolute Encoder

Its disk is etched with Gray codes or magnetic patterns — every angle maps to a unique address. Even after power loss, it comes back reporting, “I’m at 137°.” A true memory beast.

Example model：HS28D

Learn more ◆

02 Signal Output Differences

Parameter	Incremental	Absolute
Interface	TTL/HTL, differential RS-422	SSI, BiSS-C, CANopen, EtherCAT
Signal lines	2–3 (A, B, Z)	Varies the interface by protocol; even 17-bit via 2-wire serial
Noise immunity	Stable over long distances, from tens to hundreds of meters	Differential + CRC for advanced noise and safety protection

03 Resolution in Practice

Incremental

More grating lines = higher resolution, but lacks non-volatile memory — homing remains a limitation.

Absolute

Single-turn 17-bit (131,072 cpr) and beyond are mainstream; add 12-bit multi-turn (4096 turns) for a total over 29 bits.Higher precision, higher cost.

04 Startup behavior difference

Incremental Encoder

In an incremental system, if homing isn’t an option, add a battery or non-volatile counter.

Absolute Encoder

Absolute encoders are plug-and-play—ideal for safety interlocks or aerial equipment (like fans suspended mid-air that can’t “spin to find home”).

05 Application Guide

Scenario	Recommended Type	Why
High-speed motor feedback	Incremental	Pulse = speed; controllers love it
Multi-joint robotic arms	Absolute	Position recovery after power loss
PCB depaneling / repetitive cutting	Incremental	Homing acceptable, cost-efficient
Elevators / cranes	Absolute	Safety-critical — no zero reset allowed

06 Emerging Trends (2025+)

1Inductive encoders：Excellent durability and high accuracy potential

2Reflective optical encoders：All-in-one IC (LED + sensor + DSP), <3 mm thick — perfect for lightweight AGVs

3Functional safety (SIL2/PL d)：Built-in dual channels, CRC check, diagnostics — tailored for cobots

4Wireless + Energy Harvesting：Converts motion into power for multi-turn counting — goodbye batteries

07 Quick Selection Checklist

1Unstable power supply? → Absolute

2Need multi-turn? → Absolute

3Tight budget, just need speed/relative feedback? → Incremental

4Cable length >10 m? → Choose differential or serial interface

Think of it this way:
Incremental = Snapchat stories — gone after power-off.

Absolute = iCloud backup — remembers everything.
Which one fits your machine — short videl or eternal Reels

Your motion control partner — always ready to assist.

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