E8T Product Description
The E8T transmissive optical encoder is designed to provide digital quadrature encoder feedback for high volume, compact space applications. The E8T is designed to be a drop-in replacement for the E7P/E8P that offers higher maximum speed and increased output drive. The E8T utilizes an innovative, push-on code wheel that accepts shaft diameters of .118 in. to .375 in.
The E8T default encoder base provides mounting holes for two #4-40, length 0.188 in. or two M2.5, length 5mm screws on a 0.75 in. bolt circle diameter. A 1.28 in. diameter bolt circle mount is also available, only with #4-40, length 0.188 in. screws. The encoder cover is easily snapped onto the base and is marked with the connector pin-out.
The single-ended output version is connected using a 4-conductor, high retention, polarized, 1.25mm pitch connector. The differential output version uses a similar 6-pin connector. Mating cables and connectors (see the Cables/Connectors web page) are not included and are available separately.
Please Note: Due to the E8T's design, it is recommended for use as a one-time installation.
Product Specifications
View here or download the specifications
ENVIRONMENTAL
PARAMETER |
VALUE |
UNITS |
Operating Temperature |
-20 to 100 |
C |
Electrostatic Discharge, IEC 61000-4-2 Single-ended (-S option) Differential (-D option) |
± 12 ± 7 |
kV |
Vibration (10Hz to 2kHz, sinusoidal) |
20 |
G |
Shock (6 milliseconds, half-sine) |
75 |
G |
MECHANICAL
PARAMETER |
VALUE |
UNITS |
Max. Shaft Axial Play |
± .010 |
in. |
Max. Shaft Runout |
0.002 T.I.R. |
in. |
Max. Acceleration |
250000 |
rad/sec² |
Maximum RPM (1)
Maximum A/B Frequency e.x. CPR = 200, Max. RPM = 30000
|
minimum value of ((6 x 10^6)/CPR) and (60000)
100
|
RPM
kHz
|
Codewheel Moment of Inertia |
1.789 x 10^-6 |
oz-in-s² |
Mounting Screw Size Default (D-option), 1.28" base (G-option) Metric (M-option) |
#4-40 x 3/16 M2.5 x 5 |
in. mm |
Screw Bolt Circle Diameter Default (D-option), Metric (M-option) 1.28" base (G-option) |
0.75 ±0.005 1.28 ±0.005
|
in. |
Minimum Shaft Length (2) |
0.295 |
in. |
Maximum Shaft Length (2) |
0.400 (D option) / no limit (H option) |
in. |
Mounting Screw Torque |
2-3 |
in-lbs |
Technical Bulletin TB1001 - Shaft and Bore Tolerances |
Download |
(1) 60000 RPM is the maximum rpm due to mechanical considerations. The maximum RPM due to the module's maximum frequency response is dependent upon the module’s resolution (CPR).
(2) Including axial play.
PHASE RELATIONSHIP

PARAMETER |
MIN. |
TYP. |
MAX. |
UNITS |
Symmetry, S |
105 |
180 |
255 |
electrical degrees |
Quadrature Delay, Q |
30 |
90 |
150 |
electrical degrees |
(1) A leads B for clockwise shaft rotation, B leads A for counter-clockwise shaft rotation viewed from the cover 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 |
|
25 |
30 |
mA |
no load |
Low-level Output |
|
|
0.4 |
V |
IOL = 8 mA |
|
0.035 |
|
V |
no load |
High-level Output |
2.4 |
|
|
V |
IOH = -8 mA |
|
4.0 |
|
V |
no load |
Output Rise Time |
|
100 |
|
ns |
no load |
Output Fall Time |
|
50 |
|
ns |
no load |
DIFFERENTIAL ELECTRICAL
SPECIFICATIONS |
MIN. |
TYP. |
MAX. |
UNITS |
NOTES |
Supply Voltage |
4.5 |
5.0 |
5.5 |
V |
|
Supply Current |
|
27 |
32 |
mA |
no load |
Differential Output Voltage High |
4.75 |
5.0 |
|
V |
Min. @ 25mA load, Typ. @ no load |
Differential Output Voltage Low |
|
0.25 |
0.60 |
V |
Typ. @ no load, Max. @ 4.5mA load |
Differential Output Voltage |
3.0 |
3.8 |
|
V |
RL = 100 ohm |
Differential Output Rise/Fall Time |
|
|
20 |
ns |
|
PIN-OUTS
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
OPTIONS
H-OPTION (HOLE IN COVER)
The H-option adds a 0.425" diameter hole in the cover for the shaft to pass through.
M-OPTION (METRIC MOUNTING SCREWS WITH DEFAULT BASE)
Provides metric M2.5, length 5mm screws. When M-option is NOT specified the default is #4-40, length 0.188" screws. The mounting bolt circle diameter is 0.75"
G-OPTION (1.28" DIAMETER BOLT CIRCLE MOUNT)
Provides 1.28" diameter bolt circle mount in addition to 0.75" diameter bolt circle mount. Screws are #4-40, length 0.188"
ACCESSORIES
1. Centering Tool*
Part #: CTOOL - (Shaft Diameter)
Description: This reusable tool is used to accurately center the E8T base on the shaft.
2. Spacer Tool*
Part #: SPACER-E8T
Description: This reusable tool is used to properly gap the codewheel from the encoder sensor.
*Both the CTOOL and SPACER-E8T tools are included with all packaging options.
3. Screws
Part #: SCREW-440-188-PH
Description: Pan Head, Philips #4-40 UNC x 3/16"
Use: Base Mounting
Quantity Required: 2
Screws are included
Part #: SCREW-M25-5MM-PH
Description: Pan Head, Phillips M2.5 x 0.45 x 5mm
Use: Base Mounting
Quantity Required: 2
Screws are included
PRODUCT CHANGE NOTIFICATIONS
Title |
Date |
Description |
Download |
E4T, E8T Packaging - PCN 7195 |
2/16/2022 |
As part of our ongoing continuous improvement efforts, US Digital is implementing a change to our packaging options for our E4T and E8T kit encoders. |
Download |
Updated PCB on the US Digital E8T - PCN 6514 |
5/16/2018 |
This notice is to inform our customers of a PCB design change that is being implemented for the entire E8T product line. As part of our continuous improvement objective, the new PCB will improve overall product performance and enhance the robustness of this product line. The new PCB has two mounting holes that mate with the base plate instead of one hole and one slot. This change has no impact on form, fit or function for the E8T. |
Download |
E4T, S4T, and E8T Laser Markings - PCN 6227 |
8/8/2017 |
This notification is to inform our customers of a change to product markings for the E4T, E8T, and S4T series of encoders. The new marking will be utilized across all three product lines. We are making this change to improve readability for our customers and to provide consistency across the product lines. |
Download |
Additional Information
Product Notes
-
Cables and connectors are not included and must be ordered separately.
-
US Digital® warrants its products against defects in materials and workmanship for two years. See complete warranty for details.
Datasheets
Assembly Instructions
Product Change Notifications
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