Rotary Encoder - absolute and optical with hollow shaft
S21B | S21G | S21P

The S21 is a cost-effective, optical rotary encoder with a hollow shaft. It is easy to install and achieves a high data rate and resolution. The compact device has its own bearing system and a high-quality, fiberglass-reinforced plastic housing. It therefore achieves protection class IP40. The S21 offers significant performance advantages in applications that would otherwise be limited when using traditional and modular encoder solutions.

A flexible mounting bracket enables a wide range of applications. It tolerates greater shaft end mounting tolerances than other modular encoder systems.

This encoder series is able to provide different output signals: incremental or digital data formats (also with commutation signal) or analog signals (1 _Vpp). The incremental versions offer higher resolutions of over 2 million pulses per revolution.

As an alternative to the conventional digital and analog encoder signals, the absolute encoder of this series should be mentioned. The new encoder with 16-bit binary or gray code offers a high number of measuring steps per revolution. A low position error enables smooth drive behavior and remarkable positioning accuracy. High bandwidth and noise immunity ensure excellent speed, stability and control performance in industrial environments.

The S21 also supports the BiSS C protocol for incremental and absolute versions. This fast serial protocol is ideal for dynamic axes that require high acceleration, smooth speed control, excellent bidirectional repeatability and high positioning accuracy. In addition, this encoder is easy to program and configure. In addition, the mechanical dimensions are the same for all variants, which simplifies replacement and design in general.

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Features

Compact mechanical dimensions (53.34 mm outer diameter and 31.12 mm high) for easier system integration
Robust bearings with industrial ball bearings enable a shaft speed of up to 10,000 rpm
Simplified direct mount design
Software configurable resolution
Circuit protection: short circuit, reverse polarity, transient voltage suppression
ASIC-based design for excellent customization and reliability
Fast serial data communication BiSS C via RS-485 differential driver pair
High noise immunity
RoHS compliant

Options

Wide range of lines and pulses: up to 4096 incremental lines, over 2 million pulses
Range of shaft diameters: up to 12.7 mm
4, 6, 8, 10, & 12-pole commutation tracks, single-ended TTL
Absolute position data formats Gray code or binary
Absolute position value from 8- to 16-bit SSI output with user clock input pulse
Fast serial SSI communication via 2-wire or 3-wire RS-485
Absolute position value on 13-bit parallel output per user connection
Customized cable and/or connector

Absolute encoder models

Characteristics	Unit	S21B	S21G	S21P
Type		absolute, serial	absolute, serial	absolute, parallel
Output signal		SSI binary (2 or 3 lines)	SI Gray code (2 or 3 lines)	Parallel Gray code
Resolution		8 to 16 bit		8 to 16 bit	13 bit
Output frequency max.		5 MHz clock	5 MHz clock	0.3 MHz per data set
Output		SSI interface	SSI interface	TTL amplifier
Power supply		5 VDC, 45 mA	5 VDC, 45 mA	5 VDC, 60 mA
Shaft bore max.	mm	12.7
Shaft length min.	mm	6.35
shaft length max.	mm	28.58
axial shaft movement	mm	± 0.635	± 0.635	± 0.254
max. speed	rpm	10000 max
Operating temperature	°C	0 to 70	0 to 70	-40 to 85
Storage at	°C	-40 to 125	-40 to 125	-55 to 100
Relative humidity	%	90 non-condensing
Shock	g	100 (6 ms duration)
Vibration	Hz	10 - 2,000 at 10 g
Protection class		IP40