www.alliedmotion.com
© Allied Motion Technologies Inc. Specifications subject to change without notice
1
Encoders
Allied Motion’s Series 21 are cost
effective, hollow shaft optical encoders
that are easy to mount and provide high
data rate capabilities. These compact
devices have their own bearing system
and are enclosed in a high-grade glass
filled plastic resin housing with an IP40
protection rating. The Series 21 provides
significant performance benefits in
applications that would be limited by
traditional modular encoder solutions.
A flexible mount allows for much
greater tail shaft runou t and TIR than
can be tolerated by other modular
encoder designs.
The Series 21 is capable of providing
incremental digital (with commutation)
or analog formats. And the incremental
versions offer exceptional resolutions of
over 2 mil li on pul ses per revolut i on.
The Series 21 encoders are also
available in absolute formats. The new
16-bit binary or gray code absolute
provides high m easuri n g ste p count per
revolution with low position error,
enabling smoot h drive perform ance and
exceptional position accuracy. High
bandwidth and noise immunity ensure
excellent speed, stability, and command
signal response in industrial
environments.
The Series 21 also supports the BiSS C
protocol for incremental and absolute
versions. This high-speed serial protocol
is great for dynamic axes that require
high acceleration, smooth velocity
control, outstanding bi-directional
repeatability, and solid positional
stability.
Programmable and easy to configure for
a variety of output types, the Series 21
encoders simplify machine design by
allowing the same model en coder to be
used for a multitude of applications.
Features & Benefits
Compact mechanical dimensions
(2.1” O.D. x 1. 2” H) for easier
system integration
Robust bearing system
Industrial ball bearings enable up to
10,000 RPM shaft speed
Simplified direct-mount design
Software configurable resolution
Circuit protection: Short circuit,
reverse polarity, transient voltage
suppression
ASIC-based design for excellent
matching and reliability
Fast BiSS C serial data
communicat i ons vi a RS - 48 5
differential driver pair
High noise im munity
RoHS compliant
Options
Wide range of line counts and
pulses: up to 4096 lines incremental,
over 2 mil li on pul ses
Range of shaft diameters: up to
0.5 in. (12.7 mm)
4, 6, 8, 10, & 12 pole commutation
tracks, single-ended TTL
Gray code or binary a bsolute
position data format
Absolute positio n value of 8- to
16-bit SSI output per user clock
input pulse
Fast SSI serial communication via
2-wire or 3-wire RS-485
Absolute positio n value to 13-bit
parallel output per user connection
Custom cable and/or connector
Series 21 Hollow-Shaft Rotary Optical Encoders
Digital incremental or sine/cosine and absolute format
Compact, robust hollow-shaft
size-21 rotary optical encoder
Digital incremental, sine/ cosine,
or absolute format
Single-ended commutation data
for up to 12 poles
Over 2 million incremental
pulses/revolution
Absolute single-turn resolut ion of
up to 16-bit
Absolute angular position data
instantly available on power up
Fast 13-bit absolute parallel
version with data in real time
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Issued: July 17, 2015
www.alliedmotion.com
© Allied Motion Technologies Inc. Specifications subject to change without notice
2
Encoders
Series 21 Hollow-Shaft Rotary Optical Encoders
Incremental Encoder Connections
Model
S21A
S21D, S21H
S21W S21C
Connector
DF11-8DP-2V F1-W15P-HFE B10B-ZR (LF)(SN)
Signal Pin Signal Pin Signal Pin Signal Pin
NCOS 1 A 1 VDC 1 SLI+ 1
PCOS 2 A- 2 GND 2 SLI- 2
NSIN 3 B 3 N/A 3 MAO- 3
PSIN 4 B- 4 Z- 4 MAO+ 4
NZ 5 Z 5 Z 5 MA+ 5
PZ 6 Z- 6 B- 6 MA- 6
VDC 7 VDC 7 B 7 SLO- 7
GND 8 GND 8 A- 8 SLO+ 8
A 9 5 VDC 9
N/A 10 GND 10
W 11
N/A 12
V 13
N/A 14
U 15
SPECIFICATIONS - INCREMENTAL ENCODERS
Model S21A Series S21D Series S21H Series S21W Series S21C Series
Type Incremental,
sine/cosine
Incremental,
digital
Incremental,
digital, high-count
Incremental,
digital, with commutation
Incremental,
BiSS C
Format 1 Vpp, 2.5 VDC offset Differential A quad B and index Serial
Resolution
(cycles/rev;
1 cycle/rev = 4 counts/rev)
1000, 1024, 4096 1000 to 409,600
(see resolution
tables, page 6)
2000 to 2,048,000
(see resolution
tables, page 6)
2048 to 204,800
(see resolution
tables, page 6)
2000 to 2,048,000
(see resolution
tables, page 6)
Frequency Response 125 kHz max. 500 kHz 1.5 MHz 500 kHz 5 MHz Clock
Output Analog driver Line-driver CMOS line-driver Line-driver BiSS driver (75179)
Power Supply +5 VDC, 40 mA +5 VDC, 30 mA +5 VDC, 60 mA +5 VDC, 35 mA +5 VDC, 104 mA
Max. Shaft Bore, in. (mm) 0.5 (12.7)
Min. Shaft Length, in. (mm) 0.250 (6.35)
Max. Shaft Length, in. (mm) 1.125 (28.58) through-shaft option
Axial Shaft Movement, in. (mm) ±0.025 (0.635)
Max. Shaft Speed (RPM) 10,000
Mounting Pattern , in. (mm) #4-40 2-places on 1.812 (46.03) bolt circle
Operating Temp, ºC -40 to +85 -25 to +100 -25 to +85 -25 to +100 0 to +70
Storage Temp, ºC -55 to +125 -40 to +100 -55 to +125 -40 to +125
Relative Humidity 90%, non-condensing
Shock, g 100 (6 ms duration)
Vibration, Hz 10 - 2000 at 10 g
Environmental Protect ion IP 40
Issued: July 17, 2015