MA4 Miniature Absolute Magnetic Shaft Encoder

Ma4 Webproduct 01 Product Photo

MA4 Features

  • 12-bit Analog or PWM output
  • Miniature size (0.55 in. diameter)
  • -40C to 125C operating temperature range
  • Latching Connector
  • Three shaft torque options

See more info below

Configure the MA4

MA4 Miniature Absolute Encoder Product Description

Restriction of Hazardous Substances

The MA4 is a magnetic absolute encoder that reports the shaft position over 360° with no stops or gaps. This shafted encoder is available with an analog or a pulse width modulated (PWM) digital output. This is the new generation of the US Digital MA3 absolute encoder, magnetic.

Analog output provides a DC voltage that is proportional to the absolute shaft position with 12-bit resolution.

PWM output provides a pulse duty cycle that is proportional to the absolute shaft position. PWM output has 12-bit resolution with 2 different output frequency options.

Three shaft torque options are available:

  • Default (-D): sleeve bushing with higher damping for human interface applications.
  • Ball bearing (-B): miniature precision ball bearings suitable for high-speed applications (1/8" diameter shaft only).
  • Light static drag (-N): sleeve bushing with lower damping for low-speed applications.

The MA4 is connected using a 3-pin latching, 1.25mm pitch polarized connector.

Product Specifications

ENVIRONMENTAL

PARAMETER VALUE UNITS
Operating Temperature -40 to +125 C
Vibration (10Hz to 2kHz, sinusoidal) 20 G
Shock (6 milliseconds, half-sine) 75 G
Electrostatic Discharge, IEC 61000-4-2   ± 4 kV

MECHANICAL

SPECIFICATION SLEEVE BUSHING BALL BEARING
Max. Shaft Speed (1)(mechanical) 100 RPM 15000 RPM
Max. Acceleration 10000 rad/sec² 250000 rad/sec²
Max. Shaft Torque 0.5 in-oz (D-option)
0.3 in-oz (N-option)		 0.05 in-oz (B-option)
Max. Shaft Loading 2 lb. dynamic
20 lb. static		 1 lb.
Bearing Life (2) > 1000000 revolutions L10 = (28.3/Fr)³
Where L10 = bearing life in millions of revs, and Fr = radial shaft loading in pounds
Weight 0.42 oz. 0.31 oz.
Max. Shaft Runout 0.0015 in. T.I.R. 0.0015 in. T.I.R.

(1) The chip that decodes position uses sampled data. There will be fewer readings per revolution as the speed increases.  The formula for number of readings per revolution is given by:

n = 400000 / rpm

(2) only valid with negligible axial shaft loading

MOUNTING

PARAMETER VALUE UNITS
Hole Diameter 0.375 +0.005 / -0.0 in.
Panel Thickness 0.125 max. in.
Panel Nut Max. Torque 20.0 in-lbs

MATERIALS

COMPONENT MATERIAL TORQUE OPTION(S)
Shaft Stainless
Brass		 Sleeve Bushing (-D and -N options)
Ball Bearing (-B option only)
Bushing Brass -

MAGNETIC FIELD CROSSTALK

The MA4 absolute encoder contains a small internal magnet that generates a weak magnetic field extending outside the housing of each encoder. If two MA4 units are mounted closer than 1 inch apart (shaft center to center distance), install a magnetic shield such as a thin steel plate between the two encoders.  This prevents magnetic field cross-talk from causing small changes in the reported positions.

ELECTRICAL

PARAMETER MIN. TYP. MAX. UNITS
Power Supply 4.5 5.0 5.5 Volts
Supply Current   16 20 mA
Power-up Time     50 mS

ANALOG OUTPUT OPERATION

The analog output has 12-bit resolution. The analog output voltage is ratiometric to the power supply voltage, which is typically 5.0V

PARAMETER MIN. TYP. MAX. UNITS
Position Sampling Rate   6.667   kHz
Propagation Delay   286   μS
Output Noise (1-σ)   0.043   Deg. RMS
Max Output Voltage
  no load
  5k load to GND
  2k load to GND		  
4.99
4.97
4.92		   V
Min Output Voltage
  no load
  5k load to Vcc
  2k load to Vcc		  
0.010
0.030
0.075		   V
Capacitive Load     1000 pF



 

PWM OUTPUT OPERATION

The PWM duty cycle has 12-bit resolution. To measure the angular position accurately, calculate the position from the duty cycle (ton / (ton + toff )) instead of just measuring ton . This will cancel out the effect of the PWM frequency tolerance.

PARAMETER MIN. TYP. MAX. UNITS
PWM Frequency
-L option
-H option
218
874
230
920 
242
966		 Hz
PWM Duty Cycle 2.942   97.058 %
Position Sampling Rate   6.667   kHz
Propagation Delay   286   μS
Output Noise (1-σ)   0.043   Deg. RMS 
Output High Voltage
  10k load to GND
  5k load to GND		  
4.72
4.44		   V
Output Low Voltage
  10k load to Vcc
  5k load to Vcc		  
0.16
0.36		   V
Capacitive Load   1000   pF

.(1) PWM cycle time is 4351 internal clock periods. There are 4096 possible values of the duty cycle with a minimum value of (128/4351) and a maximum of (4223/4351).

 

PIN-OUTS

ANALOG OUTPUT (MA4-A):

PIN NAME DESCRIPTION
1 5 +5VDC power
2 A Analog output
3 G Ground

PWM OUTPUT (MA4-H, MA4-L):

PIN NAME DESCRIPTION
1 5 +5VDC power
2 P PWM output
3 G Ground

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

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