S4 Features
- Miniature size
- Low High retention snap-in polarized connector
- Tracks from 0 to 30,000 cycles/sec
- Ball-bearing option tracks up to 10,000 RPM
- Wide operating temperatures
- 100 to 360 cycles per revolution (CPR)
- 400 to 1,440 pulses per revolution (PPR)
- 2 channel quadrature TTL squarewave outputs

The S4 is no longer available for purchase.
The S4 is no longer available for purchase, and has been replaced by our recently released S4T. The S4T is a redesigned, enhanced version of the S4, and is already available for purchase.
S4 Product Description
The S4 miniature optical shaft encoder is a non-contacting rotary to digital converter. Useful for position feedback or manual interface, the encoder converts real-time shaft angle, speed, and direction into TTL-compatible quadrature outputs without index. The encoder utilizes a mylar disk, metal shaft, and bushing or bearing. It operates from a single +5VDC supply.
The S4 encoder is available with ball bearings for motion control applications or static drag to feel like a potentiometer for the front-panel manual interface.
The reflective sensor incorporates an LED light source and a monolithic photodetector with signal shaping electronics, providing two-channel bounceless quadrature TTL outputs.
You can connect the S4 by using a high retention 4 conductor snap-in polarized 1.25mm pitch connector. The mating connector is polarized and should attach smoothly to the encoder; do not force. See below for Cables & Connectors.
Please note: On January 16, 2012, US Digital modified the S4 part number. The S4 optical encoder is now offered with a differential output option; thus, we changed the S4 part number to accommodate either the single-ended or differential output options. The S4 part number also has a place holder added for a possible future index option. The index option is currently unavailable, and there is no projected date at which it will be made available. We also removed the current "Power" option for the S4 from the part number. The power option is very rarely selected and therefore is being eliminated from the S4 part number.
Mechanical Drawings
Specifications
ENVIRONMENTAL
PARAMETER | VALUE | UNITS |
---|---|---|
Vibration (5Hz to 2kHz) | 20 | G |
Operating Temperature | -20 to 100 | C |
Electrostatic Discharge, IEC 61000-4-2 Single-ended (S-option) Differential (D-option) |
± 3 ± 15 |
kV |
MECHANICAL
SPECIFICATION | SLEEVE BUSHING | BALL BEARING |
---|---|---|
Max. Acceleration | 10000 rad/sec² | 250000 rad/sec² |
Max. Shaft Speed | 100 rpm | 15000 rpm |
Max. Shaft Torque | 0.5 ±0.2 in-oz (D-option) 0.3 in-oz (N-option) |
0.05 in-oz |
Max. Shaft Loading | 2 lbs. dynamic 20 lbs. static |
1 lb. |
Bearing Life | > 1,000,000 revolutions | L10 = (22/Fr)³ * Where L10 = bearing life in millions of revs, and Fr = radial shaft loading in pounds |
Weight | 0.46 oz. | 0.42 oz. |
Max. Shaft Total Indicated Runout | 0.0015 in. | 0.0015 in. |
Max. Panel Nut Tightening Torque | 20 in-lbs | 20 in-lbs |
Technical Bulletin TB1001 - Shaft and Bore Tolerances | Download |
* only valid with negligible axial shaft loading.
PHASE RELATIONSHIP
PARAMETER | TYP. | MAX. | UNITS |
---|---|---|---|
Symmetry, S | 180 ± 16 | 180 ± 75 | electrical degrees |
Quadrature Delay, Q | 90 ± 10 | 90 ± 60 | electrical degrees |
(1) B leads A for clockwise shaft rotation, and A leads B for counterclockwise rotation viewed from the shaft side of the encoder.
(2) Typical values represent the encoder performance at typical mounting alignment, whereas the maximum values represent the encoder performance across the range of recommended mounting tolerance.
SINGLE-ENDED ELECTRICAL
SPECIFICATIONS | MIN. | TYP. | MAX. | UNITS | NOTES |
---|---|---|---|---|---|
Supply Voltage | 4.5 | 5.0 | 5.5 | V | |
Supply Current | 21 | 27 | mA | no load | |
Low-level Output | 0.4 | V | IOL = 6 mA | ||
High-level Output | 2.4 | V | IOH = -1 mA | ||
Rise Time | 500 | ns | CL = 25 pF, RL = 2.7 kΩ | ||
Fall Time | 100 | ns |
DIFFERENTIAL ELECTRICAL
SPECIFICATIONS | MIN. | TYP. | MAX. | UNITS | NOTES |
---|---|---|---|---|---|
Supply Voltage | 4.5 | 5.0 | 5.5 | V | |
Supply Current | 23 | 29 | mA | no load | |
Differential Output Voltage | 3.0 | 3.8 | V | RL = 100 ohm | |
Differential Output Rise/Fall Time | 20 | ns |
PIN-OUT
4-PIN SINGLE-ENDED (1) | 6-PIN DIFFERENTIAL (2) | ||
---|---|---|---|
Pin | Description | Pin | Description |
1 | +5VDC power | 1 | Ground |
2 | A channel | 2 | A channel |
3 | Ground | 3 | A- channel |
4 | B channel | 4 | +5VDC power |
5 | B channel | ||
6 | B- channel |
(1) 4-pin single-ended mating connector is CON-MIC4
(2) 6-pin differential mating connector is CON-MIC6
Notes
- For ordering information please see the Compatible Cables / Connectors section above.
- US Digital® warrants its products against defects in materials and workmanship for two years. See complete warranty for details.
Configuration Options |
S4 |
PLEASE NOTE: This chart is for informational use only. Certain product configuration combinations are not available. Visit the S4 product page for pricing and additional information. |