Click to Zoom
 Download Spec Sheet


  • Overview
  • Specifications
  • Info & Pricing

About QDH20

Quantum Devices, Inc. Model QDH20 provides an improved feedback solution in applications typically using a standard size 20 package. The QDH20 provides encoder feedback in standard industrial mounting configurations with superb mechanical and environmental protection. Outputs consist of a quadrature A & B with reference pulse Z as a standard feature. The output can be configured with either the 5 to 26 volt OL7272 line driver or open collector outputs. The QDH20 features two heavy-duty bearings holding the output shaft, and two more bearings along with an integral flexible spring mount to isolate the working pieces of the encoder from mechanical stresses.

Design Features:

  • 500 kHz fundamental frequency response
  • High operating temperature (100° C)
  • Resolutions up to 5000 lines per revolution direct read
  • Flange and servo mount options
  • Solid shaft sizes up to 10mm
  • Blind bore sizes up to 0.625″ diameter
  • High noise immunity


  • Motion control feedback
  • Machine control
  • Process control
  • Elevator controls
  • Agricultural machinery
  • Textile equipment
  • Robotics
  • Food processing
  • Conveyors
  • Material handling

Electrical Specifications

Input Voltage 4.75 to 26 VDC
Input Current Requirements 70mA typical @ 5VDC plus interface loads
Input Ripple 2% peak to peak @ 5 VDC
Output Circuits OL7272 high voltage line driver:
VOL = .5V Max @ 20mA sink
VOH = Vcc-.8V @ 20mA source
RS-422 compatible @ 20mA source
Open Collector Output Sink up to 100mA
Incremental Output Format Quadrature outputs with index pulse
See waveform reference chart in spec sheet for timing and gating options
Accuracy ±1.0 arc minute
Frequency Response 500 kHz
Symmetry 180 degrees ±10% typical
Minimum Edge Separation 67 electrical degrees at 100 kHz
Code Incremental
Rise Time Less than 1 µS
Electrical Protection Reverse protected to .6 A cont. 4 amp for 1 µS.
OL7272 outputs over voltage and short circuit protected

Environmental Specifications

Storage Temperature -40 to 125°C
Operating Temperature -20 to 100°C typical
Humidity 98% Non-condensing
Vibration 20 g's @ 50 to 500 CPS
Shock 50 g's @ 11 mS duration
Sealing Option IP 66 solid shaft, IP 64 blind bore

Mechanical Specifications

Maximum Shaft Speed 8000 RPM (see factory for higher shaft speed)
Blind Bore Diameter (Tolerance) 0.375", 0.500", 0.625" (+0.0006/-0.0000")
Solid Shaft Diameter (Tolerance) 0.250", 0.375", 10mm (+0.0000"/-0.0004")
Allowable Shaft Runout 0.001 T.I.R. (max)
Bearings Precision ABEC double shielded
Shaft Material 303 stainless Steel
Bearing Life 1.5 X 10⁹ at rated load
Moment of Inertia 3.4 X 10⁻⁴ oz-in-S²
Acceleration 1 X 10⁵ radians/sec²
Starting Torque 1.0 in-oz max
Radial Shaft Loading 40 lbs for rated bearing life, 80 lbs max
Axial Shaft Loading 40 lbs for rated bearing life, 80 lbs max
Housing Anodized Aluminum
Weight 13 oz. typical
Termination Radial Exit: 10, 7 & 6 pin MS, wire gland w/ 24" Cable
Axial Exit: 10, 7 & 6 pin MS, wire gland w/ 24" Cable
Mounting Flange w/ 1.181" female pilot
Flange w/ 1.250" male pilot
Servo w/ 1.181" female pilot
Servo w/ 1.250" male pilot
Size 25 flange and pilot
Size 25 servo and pilot
2.250" bolt circle flex mount
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