am8192b RLS, am8192b Datasheet - Page 14

• Manufacturer Part Number: am8192b
• Description: Angular Magnetic Encoder Ic
• Manufacturer: RLS

Data sheet
AM8192BD01_05
Issue 5, 14
Magnet quality and the nonlinearity error
Each AM8192B is optimized during the production to give best performance with an ideal magnet when
perfectly aligned.
An ideal magnet would have the polarization border exactly in the middle of the magnet. If the polarization is
not exactly in the middle of the magnet then the modulation of the magnetic field has an offset.
The offset represents a mean value of B
2.55 mm distance from the magnet surface and at 2.4 mm radius.
Offset will cause larger than normal integral nonlinearity errors if the AM8192B placement is not in the center
of the magnet rotation. Fig. 21 shows an additional integral nonlinearity error caused by misalignment of the
AM8192B for ideal and recommended magnets. Total integral nonlinearity is the summation of integral
nonlinearity and the additional integral nonlinearity error caused by magnet displacement.
It is important that magnetic materials are not close to the magnet because they can increase the integral
nonlinearity. They should ideally be at least 3 centimeters away from the chip. The magnet should be
mounted in a non-magnetic carrier.
© 2009 RLS d.o.o.
th
January 2009
Fig. 21: Additional integral nonlinearity error caused by magnet displacement
1.4
1.2
0.8
0.6
0.4
0.2
1
0
-0.5
Fig. 20: Ideally polarized magnet and not ideally polarized magnet
-0.25
n
Radial displacement [mm]
when the magnet is rotated trough 360° and B
0
A
0.25
associate company
0.5
Recommended
magnet
Ideal magnet
n
is measured at
14