Join us during this webinar as Encoder Products and US Digital discuss ways to avoid the most common errors when specifying encoders. Topics covered will include how knowing the difference between position accuracy and resolution aides in selecting the right encoder, as well as important mechanical, electrical, and environmental considerations.

1. Specifying the Perfect Encoder:
How to Avoid the Most Common Encoder Errors

2. Sponsored By:

3. Before We Start
q This webinar will be available afterwards at
designworldonline.com & via email
q Q&A at the end of the presentation
q Hashtag for this webinar: #DWwebinar

4. Presenter
Moderator
Miles Budimir
Design World
Jim Stevens
Dan Craner
US Digital
Encoder Products

5. EPC
ENCODER SOLUTIONS THAT
JUST MAKE SENSE

6. ABOUT EPC
•
•
•
Global designer and manufacturer of
industrial incremental and absolute
rotary encoders
Established 1969
100,000 sq ft. facility in Sagle, Idaho
7

7. THE CHALLENGE
725i-S-S-1024-R-HV-1-F-1-SX-N-N
HA52510240341
XH25D-SS-1024-ABZC-28V/V-SM18
8

8. CRITICAL CONSIDERATIONS
•
•
•
•
Package Style
Mechanical
Electrical
Environmental

9. PACKAGE STYLES

10. TWO TYPES
Bore
Shaft

11. PACKAGE STYLE SELECTION: BORE
Avoid specifying a shaft encoder when a
through-bore will be the better choice.
- Incurred additional hardware cost
- Installation
- Cost of ownership/operation– belts, pulleys,
chains, sprockets too tight
- Shaft couplings, set screws

12. PACKAGE STYLE SELECTION: SHAFT
In some applications the shaft style is preferred:
MOBILE / OUTDOOR
WASHDOWN
SEVERE CONDITIONS

13. SEALING SHAFT VS. BORE
Maintaining seal integrity of a 3/8”
shaft is much more certain than a
¾” bore

14. PACKAGE STYLE: SHAFT LOADS
Hollow bore or through-bore devices are not
commonly designed for shaft loads, but mount
free floating with a flexible anti-rotation tether.
Shaft encoders are
designed for heavy
radial/axial shaft
loading
- Measuring wheel
applications
- Axial / radial loads

15. MECHANICAL SPECIFICATION: BEARINGS
Confirm bearings are adequate for operational
axial/radial loads.
- Peak loads
- Shock
Vs.
5lbs axial/radial
80lbs axial/radial

16. MECHANICAL SPECIFICATION: BEARINGS

17. WE GET SUSPICIOUS WHEN…
“The encoder was bad out of the box.”
“All the wiring checks out.”
“Everything is fine until I get these intermittent missed
counts…and sometimes extra counts.”
“I sent the encoder back for repair and it checks out OK. I’m
still having problems.”
“It worked perfectly on the test bench, but when installed…”

18. COMMON PROBLEM: SIGNAL NOISE
Be sure to sufficiently account for electrical noise
Preferred output type: Differential Line Driver
- Complementary signals
- Error checking

19. COMMON PROBLEM: SIGNAL NOISE
Cable specifications
- Shielded cable
- Twisted Pair
Cable routing
Termination practices

20. ENVIRONMENTAL CONSIDERATIONS
A word about IP ratings….

21. ENVIRONMENTAL CONSIDERATIONS

22. 3 PATHWAYS OF INGRESS
Connector
Shaft
Seal
Case/Hub
interface

23. IP RATINGS
- Specify an appropriate IP rating for all operating conditions
- Consider all ingress pathways: shaft/bore, housing,
connector
- Understand the IP Ratings Standard
- Understand the manufacturer specifications
Shaft seals: more is not always better
- break away torque
- heat generator

24. EPC
ENCODER SOLUTIONS THAT
JUST MAKE SENSE

25. The
Truth
Behind
Kit
Encoder
Position
Accuracy

26. Introductions
–
Who
Are
We?
§ Presenter:
Jim
Stevens,
VP
of
Sales
and
Marketing
at
US
Digital
§ US
Digital
is
a
US-­‐based
manufacturer
of
Motion
Control
Products
in
Vancouver,
Washington
for
over
30
years.

27. Today
we
will
talk
about
the
positional
accuracy
of
a
kit
or
modular
style
encoder.

28. Positional
Accuracy
Misconceptions
§ Accuracy
is
cumulative
with
every
rotation
of
the
encoder
disk.
§ Accuracy
is
a
function
of
disk
to
sensor
gap
spacing.
§ Calculating
encoder
accuracy
is
nearly
impossible.

31. OR
is
“Optical
Radius”

32. Optical
Detector

33. Shaft
Optical
Detector

34. Set
Screw
Hubdisk
Shaft
Optical
Detector

35. Set
Screw
This
distance
indicates
“optical
radius”.
Hubdisk
Shaft
Optical
Detector

37. TIR
is
“Total
Indicated
Runout”

40. Perfectly
centered
disk.
No
disk
error.
Disk
Error
(none)
An
example
of
a
disk
with
a
perfect
center
rotating
correctly.

41. Disk
not
perfectly
centered
can
cause
disk
errors
Disk
Error
(offset)
Disk
off
center
rotating
incorrectly.
Disk
not
perfectly
centered
affects
accuracy

43. (TIR)
Hubdisk
and
Shaft
Formula
How
set
screw
can
affect
centering
and
accuracy.

44. Notice
set
screw.

45. Set
screw
tightened.
Hubdisk
no
longer
centered.
Hubdisk
and
Set
Screw
How
set
screw
can
affect
centering
and
accuracy.
Disk
not
perfectly
centered
affects
accuracy

48. Arc
min.
Error
Shaft
L

49. If
OR
=
0.433”
Disk
Error
=
0.001”
Shaft
ø
=
0.2498”
Hub
ø
=
0.2501”
to
0.2506”
A
Sample
Calculation

50. Solving
TIR

51. Completing
the
Equation

52. Arc
min.
14.3
180º
360º
Shaft
L

53. Thank
You!

54. Questions?
Design World
Miles Budimir
mbudimir@wtwhmedia.com
Phone: 440.234.4531
Twitter: @DW_Motion
US Digital
Jim Stevens
Jim.s@usdigital.com
Phone: 360-260-2468
Twitter: @USDigital
Encoder Products
Dan Craner
danc@encoder.com
Phone: 208-255-4700

55. Thank You
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email
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