Name: RT28 Reflective Optical Encoder Module
Brand: EPOCH
SKU: RT28
Price: Contact for quote USD
Availability: InStock

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Mechanical Dimension Drawings

RT28 Mechanical Dimension Drawing

RT28 Reflective Optical Encoder Module Mechanical Dimension Drawing

Ø28.9 mm overall diameter, 18.2 mm height. 2-Ø3.2 mounting holes. Unit: mm.

Dimensions Of Motor End Face and outgoing shaft length

RT28 Reflective Optical Encoder Module Motor End Dimension Drawing

[USES] Uses:

This product is suitable for small size DC motor, stepping motor and servo motor. Part of EPOCH's Optical Encoder Modules series designed for compact motor feedback applications.

RT28 Technical Specifications — 100~1000 CPR, 2-Channel Reflective Optical Encoder Module

Parameter	Specification
Technology	Reflective optical encoding with PCBA and code disc
Output Signals	Voltage type: A, B — Differential type: A, A/, B, B/
Resolution Range	100 ~ 1,000 CPR (10 codes: C, E, F, K, G, H, A, I, P, B)

Waveform Diagram — RT28 Series Output Timing

RT28 Optical Encoder Module Waveform Diagram - 2-Channel Quadrature Output

Two-channel quadrature output (A and B) with 90° electrical phase shift. Channel A leads Channel B for clockwise rotation (viewed from shaft end). Differential outputs A/, B/ are the inverted complements of A and B respectively.

Pin Definition — RT28 Series (6-Pin, SHR-09V-S Plug)

Line Number	1	2	3	4	5	6
Differential Definition	Vcc	Gnd	A	A/	B	B/
Voltage Type Definition	Vcc	Gnd	A	NC	B	NC

Line number

Ordering Information / Part Number — RT28 Series

Code Structure: RT28[CPR][Shaft][Year]

RT28

Series Prefix

→

CPR Code

e.g. A=500, B=1000

→

Shaft Dia. Code

e.g. 01=2mm, 06=1/4in

→

Year Code

2-digit year

CPR Code	C	E	F	K	G	H	A	I	P	B
CPR	100	200	256	300	360	400	500	512	600	1,000

Shaft Code	01	02	03	04	05	06	11	12	13	14
Diameter	2 mm	3 mm	1/8 in	5/32 in	3/16 in	1/4 in	4 mm	6 mm	8 mm	5 mm

Year Code	24	25	26
Year	2024	2025	2026

Example Ordering Code:

RT28B1324

= RT28 Series · B=1000 CPR · 13=8mm shaft · 24=Year 2024

Model Print

[CROSS-REFERENCE] Related Products

Also available: RR28 Series Miniature 3-Channel Reflective Rotary Encoder — up to 16,000 CPR with Index (Z) signal for high-precision feedback applications.

Technical FAQs — RT28 Series Reflective Optical Encoder Module

Q: RT28 vs HEDS-9000 series: what is the advantage of a reflective 2-channel encoder for DC motor feedback?

The RT28 reflective encoder eliminates the through-beam alignment required by transmissive encoders like the HEDS-9000 series, simplifying mechanical integration. With 100~1,000 CPR resolution and both voltage-type (A, B) and differential (A, A/, B, B/) output options, the RT28 supports DC motor feedback at up to 8,000 RPM across a -40°C to +85°C temperature range, using a compact 28mm PCBA+code disc design without additional bearings.

Q: What is the difference between voltage-type and differential output on the RT28 encoder module?

Voltage-type output provides single-ended A and B signals (pins 3 and 5) with pins 4 and 6 unconnected, suitable for short-distance communication within a control cabinet. Differential output provides A, A/, B, B/ on all six pins, offering common-mode noise rejection for longer cable runs in electrically noisy industrial environments. Both modes operate at 3.3V~5V supply and maintain 90° electrical phase shift quadrature timing.

Q: What CPR resolution should I choose for a 3000 RPM stepper motor with the RT28 encoder?

For a 3000 RPM stepper motor application, 500 to 1,000 CPR (codes A=500, I=512, P=600, or B=1000) is recommended for the RT28 encoder, providing sufficient position resolution for closed-loop stepper control without exceeding the 8,000 RPM maximum speed. The differential output option is recommended for stepper environments to reject electrical noise from drive cables.

Q: What shaft diameters are available for the RT28 reflective encoder module?

The RT28 reflective encoder supports 10 shaft diameter options: 2mm (01), 3mm (02), 1/8in (03), 5/32in (04), 3/16in (05), 1/4in (06), 4mm (11), 6mm (12), 8mm (13), and 5mm (14). The 28mm housing with PCBA+code disc design accommodates these sizes without adapters, compatible with a wide range of small DC and servo motors.

B2B Global RT28 Encoder Sourcing

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Need custom resolution, shaft diameter, or bulk pricing? Contact our sales team.

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Sales: liya@epoch-electronic.com

Legal Disclaimer: All manufacturer names and trademarks referenced are for cross-compatibility reference only. EPOCH is an independent manufacturer with no affiliation to OEM brands.