M3K Product Description The M3K miniature magnetic kit encoder is designed to provide shaft position feedback for high volume, restricted space applications. The M3K outputs A, B, and Index digital quadrature signals and optional pulse width modulated (PWM) absolute position. The PWM output provides a pulse width duty cycle that is proportional to the absolute shaft position.
The M3K features a push-on hub design that can easily mount from 3mm to 0.250 in. diameter shafts. The M3K consists of three components: base, push-on magnetic hub, and encoder body. Various base options accommodate different length shafts, including a 0.586 in. or 0.750 in. bolt circle. No tools are required to install the push-on, collet-gripping hub, making assembly very easy. The hub mounts to a standard shaft in seconds and provides a simple and reliable means of securing the magnet to the shaft. Two mounting screws are provided that secure the base and encoder body.
The M3K miniature magnetic encoder is connected using a Molex PicoClasp (#5013300600) 6-conductor, polarized, 1mm pitch latching connector. Mating cables and connectors (see the Cables /Connectors web page) are not included and are available separately.
Please Note: Due to the M3K's design, it is recommended for a one-time installation.
Product Specifications
ENVIRONMENTAL
PARAMETER
VALUE
UNITS
Operating Temperature
-40 to 100
C
Electrostatic Discharge, IEC 61000-4-2
±1
kV
Vibration (10Hz to 2kHz, sinusoidal)
20
G
Shock (6 milliseconds, half-sine)
75
G
MECHANICAL
PARAMETER
VALUE
UNITS
Shaft Length (1)
Max. Shaft Axial Play
±0.010
in.
Max. Shaft Runout
0.004 T.I.R.
in.
Max. Acceleration
250,000
rad/sec²
Max Hub Moment of Inertia
9.4 x 10-7
oz-in-s²
Bolt Circle Diameter Tolerance
±0.005
in.
Mounting Screw Size
Mounting Screw Torque
(1) Including axial play.
Download Technical Bulletin TB1001 - Shaft and Bore Tolerances
ELECTRICAL
PARAMETER
MIN.
TYP.
MAX.
UNITS
NOTES
Supply Voltage
4.0
5.0
16.5
V
Supply Current
17
mA
no load, 5V power
Low-level Output,
0.4
V
IOL = 4mA
High-level Output,
4.0
V
IOL = -4mA
Low-level Output,
0.5
V
IOL = 0.5mA
High-level Output,
2.5
V
IOL = -0.5mA
Output Rise/Fall Time,
25
nS
no load
Output Rise Time,
1
µS
no load
Output Fall Time,
25
nS
no load
12-bit PWM Frequency
2.0
kHz
Values up to 3.125 kHz available on request. Contact tech support.
PWM Duty Cycle range for 360 deg rotation
5
95
%
Typical values are specified at Vcc = 5.0V and 25C.
A/B/Index outputs remain at 5V logic levels for Vcc > 5.0V
PWM output is open-drain with 5k pullup to Vcc. The output is clamp limited to 6.5V Typ. for Vcc >5.0V
CPR
Max RPM (1)
Typical Count Jitter ± 2σ limits x4 quadrature decoding
Typical Angle Jitter ± 2σ limits x4 quadrature decoding
1
18720
0 counts
0 deg.
2
18720
0
0
4
18720
0
0
8
18720
0
0
16
18720
0
0
32
18720
0
0
64
18720
0
0
128
18720
0
0
256
18720
0
0
512
14648
± 1
± 0.18
1024
7324
± 1.4
± 0.12
2048
3662
± 1.4
± 0.062
4096
1831
± 2.1
± 0.05
8192
915
± 3.3
± 0.04
(1) minimum of 50 position samples per revolution
TIMING CHARACTERISTICS
PARAMETER
SYMBOL
MIN.
TYP.
MAX.
UNITS
Symmetry
X, Y
180
°e
Quadrature
Z
90
°e
Index Pulse Width
Po
90
°e
Ch. I Rise After Ch. B or Ch. A Fall
t1
10
ns
Ch. I Fall After Ch. B or Ch. A Rise
t2
10
ns
TIMING DIAGRAM
CPR
The number of Cycles (C) of the A or B outputs Per Revolution.
Index (I)
The index output goes high once per revolution, coincident with the low states of channels A and B, nominally 1/4 of one cycle (90°e).
One Shaft Rotation
360 mechanical degrees.
One Electrical Degree (°e)
1/360th of one cycle.
One Cycle (C)
360 electrical degrees (° e). Each cycle can be decoded into 1, 2, or 4 states, referred to as x1, x2, or x4 resolution multiplication.
PPR
The number of resolvable Positions Per Revolution of the encoder disk with x4 quadrature decoding.
Quadrature (Z)
The phase lag or lead between channels A and B in electrical degrees, nominally 90° e.
Symmetry
A measure of the relationship between (X) and (Y) in electrical degrees, nominally 180° e.
PIN-OUTS
PIN
DESCRIPTION
1
Ground
2
Index
3
B channel
4
+4~16.5VDC power
5
A channel
6
PWM
INCLUDED ACCESSORIES
1. CENTERING TOOL*
Part #: CTOOL - M3K - (Shaft Diameter)
Description: This reusable tool is used to accurately center the M3K base on the shaft.
2. SCREWS
Part #: SCREW-348-188-PH
Description: Pan Head, Philips #3-48 UNC x 3/16"Use: Base MountingQuantity Required: 2
Part #: SCREW-440-118-PH
Description: Pan Head, Philips #4-40 UNC x 3/16"Use: Base MountingQuantity Required: 2
Part #: SCREW-M25-5MM-PH
Description : Pan Head, Philips, M2.5 x 0.45 x 5MMUse : Base MountingQuantity Required: 2
Additional Information
Product Notes
US Digital® warrants its products against defects in materials and workmanship for two years. See complete warranty for details.
Assembly Instructions
Press Releases
3D Model Downloads
Please
configure your product first
to download a 3D model. (Note: The formats below will become links if there are 3D models available.)
SolidWorks Format
IGES Format
Parasolid Format
STEP Format
Datasheet
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