Click to Zoom
 Download Spec Sheet

QR787 Optical Rotary Encoder Shaft Style

  • Overview
  • Specifications
  • Info & Pricing

About QR787 Optical Rotary Encoder Shaft Style

Quantum Devices, Inc. Model QR787 Optical Rotary Encoder Shaft Style is intended for applications requiring high performance, high-resolution digital feedback in a very small package.  The model QR787 provides the resolution of larger encoder packages but in a package only 20 mm (0.787″) in diameter. Outputs can be configured in either single ended, 5 volt RS-422 differential or with high voltage differential line driver. QDI’s patented sensing scheme embodies a much simplified encoder design, which ultimately results in longer service life and less downtime due to feedback device failure. The encoder housing is constructed of a conductive carbon fiber composite that provides the EMI shielding of an all-metal housing and performance of a lightweight robust assembly.

Design Features:

  • Miniature Size, 20 mm (0.787″) diameter
  • Resolutions up to 2048 lines per revolution direct read
  • Single ended and differential outputs
  • Long service life
  • Conductive carbon fiber housing
  • IP50 sealing
  • High noise immunity
  • Low supply current requirements
  • RoHS construction

Note: prior to transitioning to RoHS-compliant, the product name was QD787 rather than QR787. Therefore, when cross-referencing a QD787 configuration, simply substitute the configuration prefix with QR787.


Electrical Specifications

Input Voltage 5 VDC ± 5% or 5-26 VDC
Input Current Requirements 100 mA Max. output option 01 & 02, 50mA max output
option 03; plus interface loads
Input Ripple 2% peak to peak @ 5 VDC
Output Circuits 01 = TTL output (single-ended)
02 = 26C31 line driver (RS-422)
03 = OL7272 high voltage line driver
Output Format Quadrature with A leading B for CW rotation
Ungated Z index pulse true over A and B high
Max Operating Frequency 200 kHz
Symmetry 180° electrical ± 10%
Minimum Edge Separation 54° electrical

Environmental Specifications

Storage Temperature -40 to 125°C
Operating Temperature 0 to 70°C typical
-20 to 100°C optional
Humidity 98% non-condensing
Vibration 20 g's @ 50 to 500 CPS
Shock 50 g's @ 11 ms duration

Mechanical Specifications

Maximum Shaft Speed 8000 RPM
Nominal Shaft Diameter 0.125"
Shaft Material Stainless steel
Bearings Radial ball bearing, R2 type
Radial Shaft Load 2 lb maximum
Axial Shaft Load 1 lb maximum
Housing Carbon fiber composite (case ground via connector)
Housing Volume Resistivity 10⁻² ohm·cm
Termination Two rows of 5 pins on 0.100" centers
8" ten conductor ribbon cable with 2x5 connector
Mounting Servo
Moment of Inertia 9.5x10⁻⁶ oz·in·s²
Acceleration 1x10⁵ radians/s²
Info & Pricing

More Information & Pricing

To get more information and pricing about this product, please tell us more about what you are looking for below and we can get you what you need:

Consult factory for configurations not shown (e.g. resolution, commutation, etc.).

Download Spec Sheet

Log In

Forgot Password?

Create an account

Create an account to gain access to all of our 3D models!

Create Account

Create an account to gain access to all of our 3D models!

Forgot Password