am8192b RLS, am8192b Datasheet - Page 16

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

Data sheet
AM8192BD01_05
Issue 5, 14
Analogue error signal (Error)
The error signal output (pin 2) is a magnetic error output and it can be used for alignment of the AM8192B.
The chip must be perfectly perpendicular to the axis of the magnet rotation so as to be able to use the error
signal for alignment. The error signal is sinusoidal in shape with one period per turn. The amplitude of the
error signal is proportional to the AM8192B displacement (Fig. 25). The phase of the sinusoidal error signal
(Fig. 26) is proportional to the displacement angle. To achieve optimum setup the amplitude of the error signal
should be minimized.
Digital error output (Nerr)
The digital error output can be used to check if the frequency is too high and if the magnetic signal is too low.
When no error is present the output is high. When an error is present the output is PWM modulated according
to the failure mode with a frequency of 16 Hz. If data transfer from the EEPROM at startup is faulty and
unsuccessful, then the error output is constantly low. For monitoring it is possible to connect an LED with a
1 kΩ serial resistor between Nerr and V
* The amplitude error can not detect if the magnet is too close.
** The maximum frequency depends on the resolution (see the “Interpolator” section on page 7). For resolutions below 4096 the
© 2009 RLS d.o.o.
Failure mode
No error
Amplitude error
Frequency error
Configuration
maximum frequency is 1 kHz.
2.55
2.45
2.6
2.5
2.4
0
th
January 2009
Fig. 26: Error signal shape
90
Error
Magnet rotation [°]
Fig. 25: Magnet displacement. Magnet is placed above the AM8192B
180
Nerr output
Hi
Lo/Hi= 75%
Lo/Hi= 50%
Lo
Vref
270
ss
.
Note
if amplitude is lower than 0.1 x V
if frequency is higher than maximum frequency **
360
A
25
20
15
10
5
0
0
Fig. 27: Error signal amplitude
dd
*
0.1
Displacement [mm]
associate company
0.2
0.3
16