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 20mm
dia. Absolute Optical Encoder
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Design Features:
- Miniature Size, 20mm (0.787") Diameter
- 8 bit Gray code or Binary output
- Single turn 8 bit word
- Single ended output
- Patent pending unique sensing system
- Long service life
- Conductive carbon fiber housing
- IP 50 sealing
- High noise immunity
- Low supply current requirements
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Quantum Devices, Inc. Model QD787 is intended for applications
requiring high performance, high-resolution digital feedback in
a very small package. The model QD787 provides 8 bit absolute resolution
in a package only 20mm (0.787") in diameter. Outputs can be configured
in either gray code or binary code. QDI's patent pending sensing
scheme embodies a much simplified encoder design, which ultimately
results in longer service life, and less down time 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.
Electrical Specifications
| Input Voltage |
5 VDC +/- 5% or 5-26 VDC |
| Input Current Requirements |
40 mA Max.
Plus Interface Loads |
| Input Ripple |
2% Peak to Peak @ 5 VDC |
| Output Circuits |
TTL Compatible
VOH >3.80v@-8mA, VOL <0.44v@8mA
VOH >2.50v@-20mA, VOL <0.50v@20mA |
| Output Format |
Gray code or Binary code
8 bit, single turn, single ended
Gray code option utilizes low true Chip Enable (CE') that is
pulled down with internal 10K resistor. Positive TTL signal
CE' will force the 8 bit outputs to tri-state condition allowing
for shared data paths between encoders, easing basic microprocessor
bus interfacing. |
| Frequency Response |
50 kHz |
| Directional Rotation |
Incresing code values with CW rotation (option
A256 viewed from flange side)
Incresing code values with CCW rotation on request (option
B256 view from flange side) |
| Positional Accuracy |
+/- .5LSB Maximum Error |
Environmental Specifications
| Storage Temperature |
-40 to 125oC |
| Operating Temperature |
0 to 70° C Typical
-20 to 100° C Optional (Contact
factory for more information) |
| Thermal Shutdown
(total load currents = 30mA) |
Tamb. Max Vs Input Voltage
40oC = 25.0v, 60oC = 20.0v, 80oC
= 15.0v, 100o C = 10.0v |
| 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 |
| Shaft Diameter |
0.125" |
| Shaft Material |
Stainless Steel |
| Bearings |
Radial Ball Bearing, R2 type |
| Radial Shaft Load |
2 lbs. Maximum |
| Axial Shaft Load |
1 lbs. Maximum |
| Housing |
Carbon Housing Composite (case grounded via
connector) |
| Housing Volume Resistivity |
10-2 ohm-cm |
| Termination |
8" Twelve Conductor Ribbon Cable with 2x7
Connector |
| Mounting |
Servo |
| Moment of Inertia |
9.5x10-6 oz-in-sec2 |
| Acceleration |
1x105 Radians per Second2 |
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QDI encoder distributor in your area...
To learn more about this encoder contact
us.
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