as5030 austriamicrosystems, as5030 Datasheet - Page 24

• Manufacturer Part Number: as5030
• Description: 8-bit High-speed Absolute Magnetic Rotary Encoder
• Manufacturer: austriamicrosystems

AS5030 8-bit Programmable Magnetic Rotary Encoder
The resolution of the encoder determines the smallest step size. The angle error caused by quantization cannot get better than
± ½ LSB. As shown in Figure 28, a higher resolution system (right picture) has a smaller quantization error, as the step size is
smaller.
For the AS5030, the quantization error is ± ½ LSB = ± 0.7°
Figure 29 shows a typical example of an error curve over a full turn of 360° at a given X-Y displacement. The curve includes the
quantization error, transition noise and the system error. The total error is ~2.2° peak/peak (± 1.1°).
The sawtooth-like quantization error (see also Figure 28) can be reduced by averaging, provided that the magnet is in constant
motion and there are an adequate number of samples available. The solid bold line in Figure 29 shows the moving average of
16 samples. The INL (intrinsic non-linearity) is reduced to from ~± 1.1° down to ~± 0.3°. The averaging however, also increases
the total propagation delay, therefore it may be considered for low speeds only or adaptive; depending on speed (see also: 0,
Position Error over speed ).
Rev. 1.8
-0,5
-1,5
1,5
0,5
-1
1
0
0
45
INL including quantization error
90
135
INL
www.austriamicrosystems.com
Figure 29: Typical INL error over 360°
Angle steps
180
Average (16x)
225
270
315
360
Page 24 of 33