as5035tr austriamicrosystems, as5035tr Datasheet - Page 9

• Manufacturer Part Number: as5035tr
• Description: Programmable 64ppr Incremental Magnetic Rotary Encoder
• Manufacturer: austriamicrosystems

AS5035 – 64 PPR INCREMENTAL MAGNETIC ROTARY ENCODER
For each misalignment step, the measurement as shown
in Figure 14 is repeated and the accuracy
(Err
the Z-axis in the 3D-graph.
The maximum non-linearity error on this example is
better than ± 1 degree (inner circle) over a misalignment
radius of ~0.7mm. For volume production, the placement
tolerance of the IC within the package ( ± 0.235mm) must
also be taken into account.
10.2 Transition Noise
Transition noise is defined as the jitter in the transition
between two steps.
Due to the nature of the measurement principle (Hall
sensors + Preamplifier + ADC), there is always a certain
degree of noise involved.
This transition noise voltage results in an angular
transition noise at the outputs. It is specified as 0.06
degrees rms (1 sigma)
This is the repeatability of an indicated angle at a given
mechanical position.
The transition noise influences the period, width and
phase shift of the output signals A, B and Index:
Revision 1.5
-0.1
-0.2
-0.3
-0.4
-0.5
A,B Pulse width
A-B Phase shift
0.5
0.4
0.3
0.2
0.1
Table 3: Incremental signal tolerances with transition noise
Parameter
max
Index Pulse
0
Period
width
0
– Err
°
min
)/2 (e.g. 0.25° in Figure 14) is entered as
Tolerance (1 σ )
1.406° +/-0.06°
2.813° +/-0.06°
5.625° +/-0.06°
90e° +/-1.9e°
*1
.
(rms)
90°
linearity error with centered magnet [degrees]
Tolerance (3 σ )
1.406° +/-0.18°
2.813° +/-0.18°
5.625° +/-0.18°
90e° +/-5.7e°
Figure 14: Example of linearity error over 360°
Err
(peak)
m ax
www.austriamicrosystems.com
180°
The total nonlinearity error over process tolerances,
temperature and a misalignment circle radius of 0.25mm
is specified better than ± 1.4 degrees.
The magnet used for these measurement was a
cylindrical NdFeB (Bomatec® BMN-35H) magnet with
6mm
e° = electrical degrees (see Figure 5)
*1
3 sigma represents 99.73% of readings.
The algorithm used to generate the incremental outputs
guarantees no missing or additional pulses even at high
speeds (up to 30,000 rpm and higher)
10.3 High Speed Operation
10.3.1
The AS5035 samples the angular value at a rate of 10k
samples per second. Consequently, the incremental
outputs are updated each 100µs.
At a stationary position of the magnet, this sampling rate
creates no additional error.
Incremental encoders are usually required to produce no
missing pulses up to several thousand rpm’s.
Therefore, the AS5035 has a built-in interpolator, which
ensures that there are no missing pulses at the
incremental outputs for rotational speeds of up to
10,000rpm.
: statistically, 1 sigma represents 68.27% of readings,
Err
m in
Sampling Rate
diameter
270°
and
transition noise
2.5mm
in
Page 9 of 17
360°
height.